Document:

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                                                                   Exhibit 10.19

                AMENDMENT NO. 2 TO SECURITIES PURCHASE AGREEMENT

     AMENDMENT NO. 2 TO SECURITIES PURCHASE AGREEMENT, dated as of February 4,
2000 (this "Amendment") to that certain Securities Purchase Agreement dated as
            ---------
of April 23, 1999 between BROADVIEW NETWORKS HOLDINGS, INC. (f/k/a Coaxicom,
Inc.), a Delaware corporation (the "Company"), Baker Communications Fund, L.P.
                                    -------
("Baker") and the holders of Series A Preferred Stock of the Company and Series
B Preferred Stock of the Company as listed on Schedule A of the Securities
Purchase Agreement, as amended by Amendment No. 1 ("Amendment No. 1") dated
                                                    ---------------
February 2, 2000 (the "Securities Purchase Agreement"), is made by and between
                       -----------------------------
the Company and the other parties who appear as signatories to this Amendment
(the "Purchasers").
      ----------

     WHEREAS, Section 3 of Amendment No. 1 contemplated Baker assigning the
remainder of its option (the "Baker Option") to purchase shares of 8% Series D
                              ------------
Convertible Redeemable Preferred Stock of the Company ("Series D Preferred
                                                        ------------------
Stock") to the State Treasurer of the State of Michigan, Custodian of the
Michigan Public School Employees' Retirement System, State Employees' Retirement
System and Michigan State Police Retirement System (the "State of Michigan
                                                         -----------------
Retirement Systems") on or before February 4, 2000, conditional upon the State
------------------
of Michigan Retirement Systems exercising their assigned option on or before
such date.

     WHEREAS, Baker now desires to assign the remainder of its option to the
State of Michigan Retirement Systems, and the State of Michigan Retirement
Systems desire to exercise their assigned option as of the date hereof, subject
to the terms of this Amendment, and the Company and the Purchasers desire to
approve and consent to such exercise; and

     NOW, THEREFORE, in consideration of the premises and mutual covenants and
obligations hereinafter set forth, the Company and the Purchasers hereby agree
as follows:

     SECTION 1.  Definitions.  Capitalized terms used but not otherwise defined
                 -----------
herein shall have the meaning given to them in the Securities Purchase Agreement
or, if not defined therein, in the Company's Certificate of Incorporation, as
amended.

     SECTION 2.  Amendments to Securities Purchase Agreement.  The Securities
                 -------------------------------------------
Purchase Agreement is hereby amended as of the date hereof as follows:

     (a) The first sentence is amended and restated in its entirety as follows:

               "SECURITIES PURCHASE AGREEMENT, dated as of April 23, 1999 (this
          "Agreement"), among Broadview Networks Holdings, Inc., a Delaware
          corporation (the "Company"), Baker Communications Fund, L.P.
          ("Baker"), the State Treasurer of the State of Michigan, as Custodian
          of the Michigan Public School Employees' Retirement System, State
          Employees' Retirement System and
<PAGE>

          Michigan State Police Retirement System (the "State of Michigan
          Retirement Systems"), Joel Gross and the holders of Series A Preferred
          Stock of the Company and Series B Preferred Stock of the Company
          listed on Schedule A to this Agreement (the "Holders"; the Holders,
          Baker, the State of Michigan Retirement Systems and Joel Gross being
          collectively referred to herein as the "Purchasers").

     (b)  Section 2.3 is amended and restated in its entirety as follows:
          -----------

               "The purchase price for Series D Preferred Shares shall be
          $4.66126 per Series D Preferred Share or an aggregate of Twenty Eight
          Million Dollars ($28,000,000) (the "Series D Purchase Price").  The
          Series D Purchase Price shall be paid at a closing or closings as
          described in Section 3.2 hereof by wire transfer of clearing house
          funds or by such other method as may be reasonably acceptable to the
          Company and the Purchasers, to the account of the Company as shall
          have been designated in advance to the Purchasers by the Company."

     (c)  Section 6.5(b) is amended and restated in its entirety as follows:
          --------------

               (b) The Purchasers (other than the State of Michigan Retirement
          Systems) agree to indemnify, defend and hold harmless the Company (and
          its directors, officers, members, stockholders, Employees, Affiliates,
          agents and permitted assigns) from and against any and all Losses
          based upon, arising out of or otherwise in respect of any inaccuracy
          in or breach of any representations, warranties, covenants or
          agreements of the Purchasers contained in this Agreement.

     (d)  Section 6.5 is amended to add the following as Section 6.5(c):
          -----------

               (c)  The Company is advised that as a result of an interpretation
          of the constitution of the State of Michigan by the Attorney General
          of the State of Michigan, the State of Michigan Retirement Systems are
          prohibited from agreeing to the indemnification obligations set forth
          in Section 6.5(b) of the Securities Purchase Agreement.  The Company
             --------------
          and the Purchasers agree that the State of Michigan Retirement Systems
          will have no indemnification obligations under such Section 6.5(b);
                                                              --------------
          provided that the State of Michigan Retirement Systems acknowledge and
          agree that, notwithstanding the release from the indemnification
          obligation from such Section 6.5(b), the Company and its directors,
                               --------------
          officers, members, stockholders, Employees, Affiliates, agents and
          permitted assigns shall be entitled to make a claim against the State
          of Michigan Retirement Systems for any and all losses, claims,
          liabilities, damages, deficiencies, costs or expenses (including
          interest, penalties and reasonable attorneys' fees, disbursements and
          related charges) based upon, arising out of or otherwise in respect of
          any

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          inaccuracy in or breach of any representations, warranties, covenants
          or agreements of the State of Michigan Retirement Systems contained in
          the Securities Purchase Agreement.

     (e)  Section 9.5(a) is amended and restated in its entirety as follows:
          --------------

               (a) To the fullest extent permitted by applicable law and public
          policy, the parties hereby irrevocably submit to the non-exclusive
          jurisdiction of any federal or state court located within the Borough
          of Manhattan, State of New York over any dispute arising or relating
          to this Agreement or any of the transactions contemplated hereby and
          each party hereby irrevocably agrees that all claims in respect of
          such dispute or any suit, action or proceeding related thereto may be
          heard and determined in such courts.  The parties hereby irrevocably
          waive, to the fullest extent permitted by applicable law and public
          policy, any objection which they may now or hereafter have to the
          laying of venue of any such dispute brought in such court or any
          defense of inconvenient forum for the maintenance of such dispute.
          Each of the parties hereto agrees that a judgment in any such dispute
          may be enforced in other jurisdictions by suit on the judgment or in
          any other manner provided by law.

     (f) SCHEDULE B is amended and restated in its entirety as follows:

 "Breakdown of Option to Purchase Series D Preferred Shares

Baker Communications Fund, L.P. - 2,038,075

Joel Gross - 214,534

The State of Michigan Retirement Systems - 2,038,075

The Holders - 1,716,275"

     SECTION  3. Agreement to be Bound by Securities Purchase Agreement.  Upon
                 ------------------------------------------------------
the State of Michigan Retirement Systems' execution of this Amendment, the
Securities Purchase Agreement shall be binding upon and inure to the benefit of
the State of Michigan Retirement Systems and their permitted assigns.

     SECTION  4.  No Implied Amendments.  Except as herein amended, the
                  ---------------------
Securities Purchase Agreement shall remain in full force and effect and is
ratified in all respects.  On and after the effectiveness of this Amendment,
each reference in the Securities Purchase Agreement to "this Agreement",
"hereunder", "hereof", "herein" or words of like import, and each reference to
the Securities Purchase Agreement in any other agreements, documents or
instruments

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executed and delivered pursuant to the Securities Purchase Agreement, shall mean
and be a reference to the Securities Purchase Agreement, as amended by this
Amendment.

     SECTION 5.  Effective Date.  This Amendment shall be effective as of the
                 --------------
date hereof.

     SECTION 6. Counterparts.  This Amendment may be executed by the parties
                ------------
hereto in several counterparts, each of which shall be deemed an original, but
all of which together shall constitute one and the same instrument.

                                 *   *   *   *

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    IN WITNESS WHEREOF, the parties hereto have executed, or have caused this
Amendment to be executed, by their respective officers thereunto duly
authorized, as of the date first written above.

                              BROADVIEW NETWORKS HOLDINGS, INC.

                                  /s/ Vern Kennedy
                              By:______________________________
                                      Name:
                                      Title:

                              BAKER COMMUNICATIONS FUND, L.P.

                              By:   Baker Capital Partners, LLC
                                       Its General Partner

                                  /s/ Edward Scott
                              By:______________________________
                                      Name:
                                      Title:

                                The State Treasurer of the State of Michigan,
                           as Custodian of the Michigan Public School
                        Employees' Retirement System, State Employees'
                     Retirement System and Michigan State Police
                  Retirement System

                              By:______________________________
                                      Name:
                                      Title:

                              JOEL GROSS

                              ______________________________
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                              COMMUNICATIONS VENTURES II, L.P.

                                  /s/ Roland Van der Meer
                              By:______________________________
                                      Name:
                                      Title:

                              COMMUNICATIONS VENTURES II
                                    AFFILIATES FUND, L.P.

                                  /s/ Roland Van der Meer
                              By:______________________________
                                      Name:
                                      Title:

                              NEW ENTERPRISE ASSOCIATES VII, L.P.

                                  /s/ Nancy Dorman
                              By:______________________________
                                      Name:
                                      Title:

                              WPG ENTERPRISE FUND III, L.L.C.

                              By:   WPG VC Fund Adviser, LLC.,
                                       Fund Investment Advisory Member

                              By:______________________________
                                      Name:   Barry Eggers
                                      Title:  Managing Member

                              WEISS, PECK & GREER VENTURE
                                    ASSOCIATES IV, L.L.C.

                              By:   WPG VC Fund Adviser, L.L.C.,
                                       Fund Investment Advisory Member
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                              By:________________________________
                                      Name:   Barry Eggers
                                      Title:  Managing Member

                              WPG INFORMATION SCIENCES
                                    ENTREPRENEUR FUND, L.P.

                              By:   WPG VC Fund Adviser, L.L.C.
                                       General Partner

                              By:________________________________
                                      Name:   Barry Eggers
                                      Title:  Managing Member

                              WEISS, PECK & GREER VENTURE
                                    ASSOCIATES IV CAYMAN, L.P.

                              By:   WPG VC Fund Adviser, L.L.C.,
                                    Fund Investment Advisory Partner

                              By:________________________________
                                      Name:   Barry Eggers
                                      Title:  Managing Member<PAGE>

                                                                   EXHIBIT 10.20

                            SHAREHOLDER'S AGREEMENT

     THIS SHAREHOLDER'S AGREEMENT (this "Agreement") is made and entered into
effective as of April 23, 1999 among Coaxicom, Inc., a Delaware corporation (the
"Company"), Baker Communications Fund, L.P. ("Baker"), those parties listed on
Schedule I to the (i) Series A Preferred Stock Purchase Agreement (the "Series A
Holders"), dated as of January 29, 1998, by and among the Company and the Series
A Holders, and (ii) the Series B Preferred Stock Purchase Agreement (the "Series
B Holders"), dated as of September 9, 1998, by and among the Company and the
Series B Holders (the Series A Holders and the Series B Holders are collectively
referred to herein as, the "Holders"), and each of the individuals listed on the
signature pages hereto under the heading "Founders" (collectively, the
"Founders"; the Founders, the Holders and Baker and their respective Permitted
Transferees (as defined herein) are collectively referred to herein as, the
"Stockholders").

                             W I T N E S S E T H:

     WHEREAS, Baker, the Holders and the Company have entered into a certain
Securities Purchase Agreement (the "Securities Purchase Agreement") which
provides for, among other things, (i) the purchase by Baker of 4,478,481 shares
(the "Baker Series C Preferred Shares") of 8% Series C Convertible Redeemable
Preferred Stock ("Series C Stock") of the Company for an aggregate purchase
price of Twenty Million Dollars ($20,000,000), (ii) the purchase by the Holders
of 1,791,392 shares of the Series C Stock (the "Holders' Series C Preferred
Shares"; the Holders' Series C Preferred Shares and the Baker Series C Preferred
Shares are collectively referred to herein as, the "Series C Preferred Shares")
for an aggregate purchase price of Eight Million Dollars ($8,000,000) and (iii)
an option for Baker (the "Baker Option") and the Holders to purchase up to an
aggregate of 5,300,892 shares of 8% Series D Convertible Redeemable Preferred
Stock of the Company (the "Series D Preferred Shares"; the Series C Preferred
Shares and the Series D Preferred Shares are collectively referred to herein as,
the "Priority Preferred Shares), based on their pro rata ownership of the Series
C Preferred Shares, for an aggregate additional purchase price of Twenty Eight
Million Dollars ($28,000,000); and

     WHEREAS, it is a condition precedent to the Closing of the Securities
Purchase Agreement that the parties enter into this Agreement which provides
for, among other things, certain voting rights and certain agreements with
respect to the transfer of the securities of the Company held by the parties to
this Agreement.

     NOW THEREFORE, in order to induce Baker to enter into the transactions
contemplated by the Securities Purchase Agreement, the parties hereto hereby
agree as follows:

1.   Voting Rights.  For so long as this Agreement is in effect, the
     -------------
     Stockholders shall each vote all of their securities of the Company,
     including any securities of the Company
<PAGE>

     acquired after the date of this Agreement, in favor of the size of the
     Board of Directors of the Company (the "Board") and the election of each of
     the other Stockholders' designees to the Board, or any committee thereof,
     as provided below:

     (a)  Two designees to the Board who are selected by holders of at least a
          majority in interest of the then outstanding Priority Preferred Shares
          ("Majority Priority Preferred Holders"), which shall be reconstituted
          to provide for seven (7) members to accommodate such designation
          initially consisting of the following persons: Peter Barris, Vern
          Kennedy, Ashley Leeds, Edward Scott, Philip B. Smith, Roland Van der
          Meer and Joseph M. Walsh; provided, however, that the Board shall be
                                    --------  -------
          reconstituted to provide for five (5) members no later than December
          31, 1999, at which time, the members of the Board shall continue to
          include at least two (2) designees selected by the Majority Priority
          Preferred Holders, one of whom shall have relevant industry experience
          and shall be approved by the Founders which approval shall not be
          unreasonably withheld. The two designees selected by the Majority
          Priority Preferred Holders shall have the right to serve on all of the
          Board's committees;

     (b)  Two designees to the Board who are jointly selected by the Series A
          Holders and the Series B Holders (initially Roland Van der Meer and
          Peter Barris), one of whom, following December 31, 1999, shall have
          relevant industry experience and shall be approved by the Founders
          which approval shall not be unreasonably withheld.

     (c)  Three (3) designees to the Board who are jointly selected by the
          Founders (initially Vern Kennedy, Philip B. Smith and Joseph N. Walsh)
          until the Board is reconstituted at five (5) as set forth in
          subsection 1 (a) above, at which time the Founders shall only be
          entitled to designate one (1) director to the Board.

2.   Restrictions.
     ------------

     (a)  The Company shall not take any of the following actions without the
          prior written approval of at least seventy-five percent (75%) in
          interest of the then outstanding shares held by the Series A Holders
          and Series B Holders and the holders of the Priority Preferred Shares
          (collectively, "All Preferred Holders"), voting together as a single
          class:

          (i)    amend or modify the certificate of incorporation or by-laws of
                 the Company; or

          (ii    make any material purchase or acquisition of any stock,
                 obligations or securities of, or any interest in, or make a
                 material capital contribution to,

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                 any other Person, or make any material purchase or acquisition
                 of any property or assets not used in the usual and ordinary
                 course of business.

     (b)  The Company shall not take any of the following actions without the
          prior written approval of at least a majority of the then outstanding
          shares held by All Preferred Holders:

          (i)    enter into or permit to exist any transaction or series of
                 related transactions (including, without limitation, the sale,
                 purchase, exchange or lease of assets, property or services)
                 with any Affiliate (each, an "Affiliate Transaction") or
                 extend, renew, waive or otherwise modify the terms of any
                 Affiliate Transaction, unless such transaction, series of
                 related transactions, extension, renewal, waiver or other
                 modification (i) is disclosed to all members of the Board, (ii)
                 either is approved by a majority of disinterested Directors or
                 has an aggregate value not exceeding $5,000 and (iii) is on an
                 arm's-length basis and on terms no less favorable to the
                 Company than could be obtained from non-related parties;
                 provided, however, that the foregoing shall not apply to the
                 --------  -------
                 payment of any salary or or any increase or change in salary,
                 other compensation or fringe benefit approved by the Board in
                 the manner set forth in this Section 2(b)(i) or the
                 reimbursement of expenses in the ordinary course of business;

          (ii)   incur any debt or enter into any commitments to incur debt
                 (whether by issuance, guarantee or otherwise) including vendor
                 financing and capital leases, with the exception of debt
                 incurred by the Company under the current Nortel credit
                 facilities in an amount to be approved by the majority in
                 interest of All Preferred Holders as part of its approval of
                 the quarterly budget pursuant to Section 2(b)(vii) at or prior
                 to the beginning of each calendar quarter;

          (iii)  agree to the issuance or issue any capital stock or other
                 securities convertible into or exercisable for capital stock
                 other than stock or option issuances to Employees of the
                 Company that are Excluded Events within the meaning of
                 paragraph 5.3.10(iii) of Section (C) of Article Four of the
                 Company's Amended and Restated Certificate of Incorporation;

          (iv)   purchase, redeem or otherwise acquire or retire for value any
                 capital stock or other securities convertible into or
                 exercisable for capital stock of the Company;

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          (v)    enter into any agreement, indenture or other instrument which
                 contains any provisions restricting the Company's obligation to
                 pay dividends on or make redemptions of the Priority Preferred
                 Shares;

          (vi)   declare or pay any dividend or distribution on any securities
                 ranking junior to the Priority Preferred Shares;

          (vii)  approve the quarterly budget of the Company or make any
                 expenditures not provided for in such budget; or

          (viii) sell or transfer assets in any transaction or series of related
                 transactions having a value in excess of or for a purchase
                 price in excess of Five Million Dollars ($5,000,000).

3.   Right of First Offer.  If any Stockholder who is or becomes a party to this
     --------------------
     Agreement proposes to sell (the "Selling Stockholder") any Common Stock of
     the Company or any stock or security convertible into or exchangeable for
     Common Stock of the Company, other than a sale to a Permitted Transferee,
     the Selling Stockholder shall have the obligation to first offer such
     securities to the other Stockholders (the "Non-Selling Stockholders") and
     to the Company upon the following terms:

     (a)  The Selling Stockholder shall give the Non-Selling Stockholders and
          the Company prompt written notice (the "Notice of Intent") of its
          intent to sell such securities of the Company. The Company and the
          Non-Selling Stockholders shall have the exclusive right for a period
          of fifteen (15) business days from the date on which the Notice of
          Intent was given (the "Exclusivity Period") to make a firm offer to
          purchase such securities on terms satisfactory to the Selling
          Stockholder. The Company shall have the first priority in respect of
          any such purchase and if the Company does not make an offer acceptable
          to the Selling Stockholder, each Non-Selling Stockholder who is
          willing to purchase the securities on terms acceptable to the Selling
          Stockholder shall have the right to participate in such purchase,
          based upon their respective pro rata ownership of the Fully Diluted
          Common Stock. If, upon the expiration of the Exclusivity Period, the
          Selling Stockholder, the Company and the Non-Selling Stockholders are
          unable to come to terms with respect to the purchase and sale of such
          securities, the Selling Stockholder shall have the right to sell such
          securities to a third party. The Selling Stockholder shall not enter
          into discussions with any third party regarding the sale of such
          securities during the Exclusivity Period; and

     (b)  If, after following the procedures set forth in Section 2(a), the
          Selling Stockholder receives an offer from a third party for such
          securities on terms and conditions that it deems acceptable (but on
          terms no less favorable to the Selling Stockholder

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<PAGE>

          than the Company or the Non-Selling Stockholders shall have offered
          pursuant to Section 3(a)), the Selling Stockholder may sell such
          securities to such third party, provided that such sale takes place
                                          --------
          within ninety (90) days after the expiration of the Exclusivity
          Period. If no such sale occurs during such ninety (90) day period, any
          attempted sale of such securities shall be subject to the right of
          first offer by the Non-Selling Stockholders set forth in this Section
          3.

4.   Tag Along Rights.  After complying with the terms of Section 3 of this
     ----------------
     Agreement, if any Selling Stockholder proposes to sell or transfer, in one
     transaction or in a series of related transactions (a "Tag Along Sale"),
     any securities of the Company owned by such Selling Stockholder to any
     third party, other than a sale or transfer to a Permitted Transferee or to
     the Company or to Non-Selling Stockholders pursuant to Section 3 of this
     Agreement, the Non-Selling Stockholders shall have the right to participate
     in such Tag Along Sale on the following terms:

     (a)  The Selling Stockholder shall give the Non-Selling Stockholders not
          less than thirty (30) days' written notice (a "Sale Notice") of its
          intention, describing the price offered, all other material terms and
          conditions of the Tag Along Sale and, if the consideration payable
          pursuant to the Tag Along Sale consists in whole or in part of
          consideration other than cash, such information relating to such other
          consideration as investors may reasonably request and which is
          available to the Selling Stockholder.

     (b)  In connection with any Tag Along Sale, the Non-Selling Stockholders
          shall have the right, in their sole discretion, to sell, for the same
          price per share being paid to, and otherwise on the same terms and
          conditions as, the Selling Stockholder, its pro rata portion of the
          aggregate amount of Fully Diluted Common Stock being sold in the Tag
          Along Sale, determined by multiplying the number of securities being
          sold in the Tag Along Sale by a fraction, the numerator of which is
          the number of shares of Fully Diluted Common Stock held by such Non-
          Selling Stockholder and the denominator of which is the number of
          shares of Fully Diluted Common Stock.

     (c)  The Non-Selling Stockholders must exercise their "tag along" rights by
          giving written notice to the Selling Stockholder within thirty (30)
          days of the delivery of a Sale Notice, specifying the number of
          securities that such Non-Selling Stockholder desires to include in the
          Tag Along Sale. At the closing of the Tag Along Sale, against payment
          of the purchase price for the securities to be sold by each Non-
          Selling Stockholder, each Non-Selling Stockholder will deliver to the
          third party the certificate or certificates representing such number
          of securities, duly endorsed, together with all other documents which
          are necessary in order to effect such Tag Along Sale. The Selling
          Stockholder shall use its best efforts to

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<PAGE>

          obtain the agreement of the prospective transferee(s) to the
          participation of the Non-Selling Stockholders in any contemplated Tag
          Along Sale. No party to this Agreement shall transfer any of its
          securities to any prospective transferee if such prospective
          transferee declines to allow a Non-Selling Stockholder to participate
          in a Tag Along Sale.

5.   Source of Financing.  If the Company determines to raise capital through
     -------------------
     the issuance of any Common Stock or any stock or security convertible into
     or exchangeable for Common Stock (an "Equity Financing") in a transaction
     or transactions not involving an issuance referred to in Section 6(a)(1),
     (ii) or (iii), then All Preferred Holders shall have the right to first
     offer to provide the Equity Financing to the Company on the following
     terms:

     (a)  The Company shall give All Preferred Holders prompt written notice (a
          "Financing Notice") of its determination, describing the material
          terms and conditions of the Equity Financing. All Preferred Holders
          shall have the exclusive right for a period of fifteen (15) business
          days from the date on which the Financing Notice was given (the
          "Financing Exclusivity Period") to make a firm offer to provide the
          Equity Financing on terms satisfactory to the Company. If, upon the
          expiration of the Financing Exclusivity Period, the best offer (the
          "Best Offer") of either the Series A and Series B Holders, on the one
          hand, or the holders of the Priority Preferred Shares, on the other
          hand, is unacceptable to the Company with respect to the Equity
          Financing, the Company shall have the right to approach other sources
          to provide the Equity Financing. If the Company accepts the Best
          Offer, all Stockholders shall have preemptive rights to participate in
          such financing in the manner set forth in Section 6. The Company shall
          not enter into discussions with any financing source other than All
          Preferred Holders during the Financing Exclusivity Period.

     (b)  If, after following the procedures set forth in Section 5(a), the
          Company receives a financing proposal from an alternative financing
          source on terms and conditions that it deems acceptable (but on terms
          more favorable to the Company than the Best Offer), the Company shall
          be entitled to accept such alternative proposal and close within 120
          days of the expiration of the Financing Exclusivity Period. Subject to
          any confidentiality obligations to which the Company is then subject,
          the Company shall notify All Preferred Holders and keep such holders
          fully apprised of such alternative proposal, including the status of
          negotiations with respect thereto. After such 120-day period, the
          Company must comply with the right of first offer to All Preferred
          Holders pursuant to the terms of this Section 5.

6.   Preemptive Rights.  In addition to the rights of All Preferred Holders
     -----------------
     provided in Section 5 hereof, all Stockholders shall be entitled to certain
     preemptive rights as follows:

                                       6
<PAGE>

     (a)  Except for the issuance of the Company's capital stock or other
          securities (i) pertaining to options or rights to acquire shares of
          capital stock existing on the date hereof, (ii) pursuant to a public
          offering if the managing underwriter of such public offering advises
          the Company in writing that in its opinion it is necessary for the
          Stockholders to waive its preemptive rights granted hereunder in order
          for the public offering to achieve its maximum benefit, or (iii)
          comprising additional stock or option issuances to Employees of the
          Company that are Excluded Events within the meaning of paragraph
          5.3.10(iii) of Section (C) of Article Four of the Company's Amended
          and Restated Certificate of Incorporation, if the Company at any time
          after the date hereof authorizes the issuance or sale of any capital
          stock of the Company or any securities of the Company containing
          options or rights to acquire any shares of capital stock (other than
          as a dividend on the outstanding capital stock), the Company shall
          first offer to sell to the Stockholders a portion of such capital
          stock or other securities equal to the percentage of Fully Diluted
          Common Stock held by each Stockholder at the time of such issuance. In
          the event any of the Stockholders elect not to exercise their
          preemptive rights with respect to any issuance of capital stock or
          other securities by the Company, the remaining Stockholders shall have
          the right to purchase such unsubscribed portion on a pro rata basis,
          based on the percentage of Fully Diluted Common Stock held by each
          remaining Stockholder at the time of such issuance.

     (b)  In order to exercise their purchase rights hereunder, the Stockholders
          must, within 10 business days after receipt of written notice from the
          Company describing in reasonable detail the capital stock or
          securities being offered, the purchase price thereof and the payment
          terms, deliver a written notice to the Company describing its election
          hereunder. The Company shall give the Stockholders no less than 15
          business days notice of the closing of the sale and purchase of such
          shares.

     (c)  Upon the expiration of the 10-day period described above, the Company
          shall be entitled to sell such capital stock or securities which the
          Stockholders have elected not to purchase during the 120 days
          following such expiration on terms and conditions no more favorable to
          the purchasers thereof than those offered to the Stockholders. Any
          capital stock or securities offered or sold by the Company to any
          Person after such 120-day period must be reoffered to the Stockholders
          pursuant to the terms of this Section 6.

7.   Year 2000 Covenant.  The Company undertakes to promptly inform the Series A
     ------------------
     and Series B Holders and the holders of the Priority Preferred Shares of
     any material deficiency or expected cost in complying with the Year 2000
     Problem.

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<PAGE>

8.   Maintenance of Insurance.  The Company shall maintain in full force and
     ------------------------
     effect the present levels of insurance set forth on Schedule A to this
     Agreement to the extent such insurance remains available on commercially
     reasonable terms.

9.   Registration Rights.
     -------------------

     9.1. Demand Registrations.
          ---------------------

     (a)    Requests for Registration.  Subject to Section 9.1(b) below, the
            -------------------------
            Majority Priority Preferred Holders may at any time after the first
            to occur of (x) a Qualified Public Offering or (y) the fifth
            anniversary of the issuance of the Series C Preferred Shares, and
            the Series A and Series B Holders owning a majority in interest of
            the Series A Preferred Stock and the Series B Preferred Stock of the
            Company (the "Majority Series A/B Holders") may at any time after
            the first to occur of (x) a Qualified Public Offering or (y) the
            sixth anniversary of issuance of the Series C Preferred Shares,
            request registration under the Securities Act of all or part of
            their Registrable Securities on Form S-1, or any similar long-form
            of registration, or, if available on Form S-2 or S-3 or any similar
            short-form of registration. Each request for a Demand Registration
            shall specify the number of Registrable Securities requested to be
            registered and the proposed underwriter. Within 10 days after
            receipt of any such request, the Company will give written notice of
            such requested registration to all other holders (if any) of
            Registrable Securities and, subject to Section 9.1(d) below, will
            include in such registration all Registrable Securities with respect
            to which the Company has received written requests for inclusion
            therein within 15 days after the receipt of the Company's notice.
            All registrations requested pursuant to this Section 9.1(a) are
            referred to herein as "Demand Registrations."

     (b)    Registrations.  The Majority Priority Preferred Holders and the
            -------------
            Majority Series A/B Holders are each entitled to request (i) one (1)
            Demand Registration to compel the Company to effect an initial
            public offering and (ii) two (2) Demand Registrations after a
            Qualifying EPO. In each such case, the Company will pay all
            Registration Expenses (as defined in Section 9.5 hereto). A
            registration will not count as one of such Demand Registrations
            until it has become effective and, if such offering is an
            underwritten offering, the holders of Registrable Securities have
            sold all securities requested to be included thereunder (exclusive
            of securities registered to cover underwriters' over-allotment
            options).

     (c)    Priority in Demand Registration.  If a Demand Registration is an
            -------------------------------
            underwritten offering and the managing underwriters advise the
            Company in writing that in their opinion the number of Registrable
            Securities and, if permitted hereunder, other securities requested
            to be included in such offering exceeds the number of

                                       8
<PAGE>

            Registrable Securities and other securities, if any, which can be
            sold therein without adversely affecting the marketability of the
            offering (the "Offering Quantity"), the Company will include in such
            registration securities in the following priority:

            (i)     For a demand made by the Majority Priority Preferred Holders
                    prior to a Qualified Public Offering and the sixth
                    anniversary of issuance of the Series C Preferred Shares (a
                    "Priority Registration"), all Registrable Securities owned
                    by the Priority Preferred holders.

            (ii)    For any demand which is not a Priority Registration, first,
                    all Registrable Securities requested to be included by any
                    holders thereof, and if the number of such holders'
                    securities requested to be included exceeds the Offering
                    Quantity, then the Company shall include an equal number of
                    shares from (a) the Holders of the Series A Preferred Stock
                    and the Series B Preferred Stock of the Company and (b) the
                    holders of the Priority Preferred Shares, with such shares
                    to be allocated among the holders within each series of
                    preferred stock based on the amount of Registrable
                    Securities held by the particular holders in each class on
                    an as converted basis; and

            (ii)    second, to the extent (and only to the extent) that the
                    Offering Quantity exceeds the aggregate amount of securities
                    to be sold for the account of the holders of Registrable
                    Securities which are requested to be included in such
                    registration, the Company will include in such registration
                    any other securities requested to be included in such
                    offering, and if the number of such other holders'
                    securities requested to be included exceeds the Offering
                    Quantity, then the Company shall include only each such
                    requesting holder's pro rata share of the Offering Quantity,
                    based on the amount of securities held by such holder, on an
                    as converted basis.

     (d)    Restrictions on Demand Registrations.  The Company will not be
            ------------------------------------
            obligated to effect any Demand Registration within 120 days after
            the effective date of a previous Demand Registration or other
            registration of securities of the Company that is an underwritten
            offering.

     (e)    Selection of Underwriters.  In connection with a Demand Registration
            -------------------------
            and any other registration of securities of the Company that is an
            underwritten offering, the Board shall have the right to select the
            lead book-running manager to administer the offering, such selection
            to be subject to the approval of the Majority Priority Preferred
            Holders and the Majority Series A/B Holders which approval shall not
            be unreasonably withheld.

                                       9
<PAGE>

     (f)    Other Registration Rights. Except as provided in this Agreement, the
            -------------------------
            Company will not grant to any Persons the right to demand that the
            Company register any equity securities of the Company, or any
            securities convertible into or exchangeable or exercisable for such
            securities, without the prior written consent of the Majority Series
            A/B Holders and the Majority Priority Preferred Holders.

     (g)    Demand Registrations Expenses.  The Registration Expenses of the
            -----------------------------
            holders of Registrable Securities will be paid by the Company in all
            Demand Registrations.

     9.2.   Piggyback Registrations.
            ------------------------

     (a)    Right to Piggyback. Whenever the Company proposes to register any of
            ------------------
            its securities under the Securities Act (other than pursuant to a
            Demand Registration or a registration on Form S-4 or S-8 or any
            successor or similar forms) and the registration form to be used may
            be used for the registration of Registrable Securities, whether or
            not for sale for its own account, the Company will give prompt
            written notice to all holders of Registrable Securities of its
            intention to effect such a registration and will include in such
            registration all Registrable Securities with respect to which the
            Company has received written requests for inclusion therein within
            30 days after the receipt of the Company's notice (a "Piggyback
            Registration").

     (b)    Piggyback Expenses.  The Registration Expenses of the holders of
            ------------------
            Registrable Securities will be paid by the Company in all Piggyback
            Registrations.

     (c)    Priority on Primary Registrations. If a Piggyback Registration is an
            ---------------------------------
            underwritten primary registration on behalf of the Company, and the
            managing underwriters advise the Company in writing (with a copy to
            each party hereto requesting registration of Registrable Securities)
            that in their opinion the number of securities requested to be
            included on a secondary basis in such registration exceeds the
            number which can be sold in such offering without adversely
            affecting the marketability of such primary or secondary offering
            (the "Company Offering Quantity"), the Company will include in such
            registration securities in the following priority:

            (i)     first, the Company will include the securities the Company
                    proposes to sell; and

            (ii)    second, the Company will include all Registrable Securities
                    and all other securities of the Company requested to be
                    included by any holders thereof, and if the number of such
                    holders' securities requested to be included exceeds the
                    Company Offering Quantity, then the Company shall include

                                       10
<PAGE>

                    an equal number of shares of (a) the Holders of the Series A
                    Preferred Stock and the Series B Preferred Stock of the
                    Company and (b) the holders of the Priority Preferred
                    Shares, with such shares to be allocated among the holders
                    within each series of preferred stock on a pro rata basis,
                    based on the amount of securities held by the particular
                    holders in each class on an as converted basis.

     (d)    Other Registrations.  If the Company has previously filed a
            -------------------
            registration statement with respect to Registrable Securities
            pursuant to Section 9.1 or pursuant to this Section 9.2, and if such
            previous registration has not been withdrawn or abandoned, the
            Company will not file or cause to be effected any other registration
            of any of its equity securities or securities convertible into or
            exchangeable or exercisable for its equity securities under the
            Securities Act (except on Form S-4 or S-8 or any successor or
            similar form), whether on its own behalf or at the request of any
            holder or holders of such securities, until a period of at least 120
            days has elapsed from the date on which such previous registration
            statement was declared effective by the Securities Exchange
            Commission.

     9.3.   Holdback Agreements.
            -------------------

     (a)    To the extent not inconsistent with applicable law, the holders of
            Registrable Securities agree not to effect any public sale or
            distribution (including sales pursuant to Rule 144 of the Securities
            Act) of any securities of the Company, or any securities, options or
            rights convertible into or exchangeable or exercisable for such
            securities that the holders of Registrable Securities own prior to
            the effective date of any registration statement and during the
            seven days prior to and the 120-day period beginning on such
            effective date, unless (in the case of an underwritten public
            offering) the managing underwriters otherwise agree; provided that
                                                                 --------
            such restrictions shall not be more restrictive in duration or scope
            than restrictions imposed on (i) any Person which has been granted
            registration rights by the Company, (ii) any officer or director of
            the Company or (iii) any 5% or greater holder of equity securities
            of the Company; and provided further, that such restriction shall
                                -------- -------
            not apply to equity securities purchased in or after such
            underwritten registration.

     (b)    The Company agrees (i) not to effect any public sale or distribution
            of its equity securities, or any securities convertible into or
            exchangeable or exercisable for such securities, during the seven
            days prior to and during the 120-day period beginning on the
            effective date of any underwritten Demand Registration or any
            underwritten Piggyback Registration (except as part of such
            underwritten registration or pursuant to registrations on Form S-4
            or S-8 or any successor or similar form), unless the underwriters
            managing the public offering otherwise

                                       11
<PAGE>

            agree, and (ii) to cause each holder of its Common Stock, or any
            securities convertible into or exchangeable or exercisable for
            Common Stock, purchased from the Company at any time after the date
            of this Agreement (other than in a public offering) to agree not to
            effect any public sale or distribution (including sales pursuant to
            Rule 144 of the Securities Act) of any such securities during such
            period (except as part of such underwritten registration, if
            otherwise permitted), unless the underwriters managing the public
            offering otherwise agree.

     9.4.   Registration Procedures.  Whenever any Registrable Securities are
            -----------------------
required to be registered pursuant to this Agreement, the Company will use its
best efforts to effect the registration and the sale of such Registrable
Securities in accordance with the intended method of disposition thereof, and
pursuant thereto the Company will as expeditiously as possible:

     (a)    prepare and within 60 days (or 45 days with respect to any short-
            form Registration) after the end of the period within which requests
            for registration may be given to the Company file with the
            Securities and Exchange Commission a registration statement with
            respect to such Registrable Securities and thereafter use its best
            efforts to cause such registration statement to become effective
            (provided that before filing a registration statement or prospectus
             --------
            or any amendments or supplements thereto, the Company will furnish
            to the counsel selected by the holders of a majority of the
            Registrable Securities initiating such registration statement copies
            of all such documents proposed to be filed, which documents will be
            subject to review of such counsel); provided, however, that the
                                                --------  -------
            Company may postpone for not more than 90 calendar days the filing
            or effectiveness of a registration statement requested under Section
            9.1 hereof if the Company determines that such registration could
            reasonably be expected to have a material adverse effect on any
            proposal or plan by the Company to engage in any acquisition of
            assets (other than in the ordinary course of business) or any
            merger, consolidation, tender offer or similar transaction then
            under consideration; but in such event, the Majority Series A/B
            Holders or the Majority Priority Preferred Holders, whichever has
            made a demand for such registration, shall be entitled to withdraw
            such request, and if such request is withdrawn such registration
            will not count as a Demand Registration under Section 9.1 hereof;

     (b)    prepare and file with the Securities and Exchange Commission such
            amendments and supplements to such registration statement and the
            prospectus used in connection therewith as may be necessary to keep
            such registration statement effective for a period of either (i) not
            less than 270 days (subject to extension pursuant to Section 9.7(b))
            or, if such registration statement relates to an underwritten
            offering, such longer period as in the opinion of counsel for the
            underwriters a prospectus is required by law to be delivered in
            connection with sales of Registrable Securities by an underwriter or
            dealer or (ii) such shorter

                                       12
<PAGE>

            period as will terminate when all of the securities covered by such
            registration statement have been disposed of in accordance with the
            intended methods of disposition by the seller or sellers thereof set
            forth in such registration statement (but in any event not before
            the expiration of any longer period required under the Securities
            Act), and to comply with the provisions of the Securities Act with
            respect to the disposition of all securities covered by such
            registration statement until such time as all of such securities
            have been disposed of in accordance with the intended methods of
            disposition by the seller or sellers thereof set forth in such
            registration statement;

     (c)    furnish to each seller of Registrable Securities such number of
            copies of such registration statement, each amendment and supplement
            thereto, the prospectus included in such registration statement
            (including each preliminary prospectus) and such other documents as
            such seller may reasonably request in order to facilitate the
            disposition of the Registrable Securities owned by such seller;

     (d)    use its best efforts to register or qualify such Registrable
            Securities under such other securities or blue sky laws of such
            jurisdictions as any seller reasonably requests and do any and all
            other acts and things which may be reasonably necessary or advisable
            to enable such seller to consummate the disposition in such
            jurisdictions of the Registrable Securities owned by such seller
            (provided that the Company will not be required to (i) qualify
            generally to do business in any jurisdiction where it would not
            otherwise be required to qualify but for this subparagraph, (ii)
            subject itself to taxation in any such jurisdiction or (iii) consent
            to general service of process in any such jurisdiction);

     (e)    notify each seller of such Registrable Securities, at any time when
            a prospectus relating thereto is required to be delivered under the
            Securities Act, of the happening of any event (a "Changing Event")
            as a result of which, the prospectus included in such registration
            statement contains an untrue statement of a material fact or omits
            any fact necessary to make the statements therein not misleading in
            the light of the circumstances under which they were made, and, at
            the request of any such seller, the Company will as soon as possible
            prepare and furnish to such seller (a "Correction Event") a
            reasonable number of copies of a supplement or amendment to such
            prospectus so that, as thereafter delivered to the purchasers of
            such Registrable Securities, such prospectus will not contain an
            untrue statement of a material fact or omit to state any fact
            necessary to make the statements therein not misleading in the light
            of the circumstances under which they were made;

                                       13
<PAGE>

     (f)    use best efforts to cause all such Registrable Securities to be
            listed on each securities exchange on which similar securities
            issued by the Company are then listed and, if not so listed, to be
            listed on the NASD automated quotation system;

     (g)    provide a transfer agent and registrar for all such Registrable
            Securities not later than the effective date of such registration
            statement;

     (h)    enter into such customary agreements (including underwriting
            agreements in customary form) and take all such other actions as the
            holders of a majority of the Registrable Securities being sold or
            the underwriters, if any, reasonably request in order to expedite or
            facilitate the disposition of such Registrable Securities
            (including, without limitation, effecting a stock split or a
            combination of shares);

     (i)    make available for inspection by any seller of Registrable
            Securities, any underwriter participating in any disposition
            pursuant to such registration statement and any attorney, accountant
            or other agent retained by any such seller or underwriter, all
            financial and other records, pertinent corporate documents and
            properties of the Company, and cause the Company's officers,
            directors, Employees and independent accountants to supply all
            information reasonably requested by any such seller, underwriter,
            attorney, accountant or agent in connection with such registration
            statement;

     (j)    otherwise use its best efforts to comply with all applicable rules
            and regulations of the Securities and Exchange Commission, and make
            available to its security holders, as soon as reasonably
            practicable, an earnings statement covering the period of at least
            twelve months beginning with the first day of the Company's first
            full calendar quarter after the effective date of the registration
            statement, which earnings statement shall satisfy the provisions of
            Section 11(a) of the Securities Act and Rule 158 thereunder;

     (k)    in the event of the issuance of any stop order suspending the
            effectiveness of a registration statement, or of any order
            suspending or preventing the use of any related prospectus or
            suspending the qualification of any securities included in such
            registration statement for sale in any jurisdiction, the Company
            will use its reasonable best efforts promptly to obtain the
            withdrawal of such order;

     (l)    use its best efforts to obtain one or more comfort letters, dated
            the effective date of such registration statement (and, if such
            registration includes a public offering, dated the date of the
            closing under the underwriting agreement), signed by the Company's
            independent public accountants in customary form and covering such
            matters of the type customarily covered by comfort letters as the
            holders of a majority of the Registrable Securities being sold
            reasonably request; and

                                       14
<PAGE>

     (m)    use its best efforts to provide a legal opinion of the Company's
            outside counsel, dated the effective date of such registration
            statement (and, if such registration includes a public offering,
            dated the date of the closing under the underwriting agreement),
            with respect to the registration statement, each amendment and
            supplement thereto, the prospectus included therein (including the
            preliminary prospectus) and such other documents relating thereto in
            customary form and covering such matters of the type customarily
            covered by legal opinions of such nature.

The Company may require each seller of Registrable Securities as to which any
registration is being effected to furnish the Company such information regarding
such seller and the distribution of such securities as the Company may from time
to time reasonably request in writing.  No filing under subparagraph 9.4(a) or
9.4(b) shall be deemed late, in default of the Company's obligations thereunder,
or otherwise defective, if it occurs after the times indicated in such
subparagraphs solely as a result of any delay by any seller of Registrable
Securities in furnishing the information called for pursuant to the preceding
sentence.

     9.5.   Registration Expenses.
            ---------------------

     (a)    All expenses incident to the Company's performance of or compliance
            with this Agreement, including, without limitation, all registration
            and filing fees, fees and expenses of compliance with securities or
            blue sky laws, printing expenses, messenger and delivery expenses,
            and fees and disbursements of counsel for the Company and all
            independent certified public accountants, underwriters (excluding
            discounts and commissions, which will be paid by the sellers of
            Registrable Securities) and other Persons retained by the Company
            (all such expenses being herein called "Registration Expenses"),
            will be borne as provided in this Agreement, and the Company will,
            in any event, pay its internal expenses (including, without
            limitation, all salaries and expenses of its Employees performing
            legal or accounting duties), the expense of any annual audit or
            quarterly review, the expense of any liability insurance and the
            expenses and fees for listing the securities to be registered on
            each securities exchange on which similar securities issued by the
            Company are then listed or on the NASD automated quotation system.

     (b)    In connection with each Demand Registration (including registration
            pursuant to Section 9.10) and Piggyback Registration, the Company
            will reimburse the holders of Registrable Securities for the
            reasonable fees and disbursements of one counsel chosen by the
            holders of a majority of the Registrable Securities who request
            inclusion in such registration.

                                       15
<PAGE>

     (c)    To the extent Registration Expenses are not required to be paid by
            the Company, each holder of Registrable Securities and any other
            holder of securities included in any registration hereunder will pay
            those Registration Expenses allocable to the registration of such
            holder's Registrable Securities or other securities, as the case may
            be, so included, and any Registration Expenses not so allocable will
            be borne by all sellers of Registrable Securities and any other
            holders of securities included in such registration in proportion to
            the aggregate selling price of the securities to be so registered.

     9.6.   Indemnification.
            ---------------

     (a)    The Company agrees to indemnify and hold harmless, to the extent
            permitted by law, each holder of Registrable Securities and its
            Representatives against any Losses, joint or several, to which such
            holder of Registrable Securities or its Representatives may become
            subject under the Securities Act or otherwise, insofar as such
            Losses (or actions or proceedings, whether commenced or threatened,
            in respect thereto arise out of or are based upon (i) any untrue or
            alleged untrue statement of material fact contained in any
            registration statement, prospectus or preliminary prospectus or any
            amendment or supplement thereto or (ii) any omission or alleged
            omission of a material fact required to be stated therein or
            necessary to make the statements therein not misleading, and the
            Company will reimburse such holder of Registrable Securities and its
            Representatives for any legal or any other expenses incurred by them
            in connection with investigating or defending any such Loss, action
            or proceeding, provided, however, that the Company shall not be
                           --------  -------
            liable to any such holder in any such case to the extent that any
            such Loss (or action or proceeding, whether commenced or threatened,
            in respect thereof) arises out of or is based upon an untrue
            statement or alleged untrue statement, or omission or alleged
            omission, made in such registration statement, any such prospectus
            or preliminary prospectus or any amendment or supplement thereto, in
            reliance upon, and in conformity with, written information prepared
            and furnished to the Company by such holder of Registrable
            Securities or its Representatives expressly for use therein or by
            failure of such holder of Registrable Securities to deliver a copy
            of the registration statement or prospectus or any amendments or
            supplements thereto after the Company has furnished such holder of
            Registrable Securities with a sufficient number of copies of the
            same. In connection with an underwritten offering, the Company will
            indemnify such underwriters, their officers and directors and each
            Person who controls such underwriters (within the meaning of the
            Securities Act) to the same extent as provided above with respect to
            the indemnification of the holders of Registrable Securities.

                                       16
<PAGE>

     (b) In connection with any registration statement in which the holders of
         Registrable Securities are participating, the holders of Registrable
         Securities will furnish to the Company in writing such information and
         affidavits as the Company reasonably requests for use in connection
         with any such registration statement or prospectus and, to the extent
         permitted by law, each such holder of Registrable Securities will
         indemnify and hold harmless the Company, its directors and officers and
         each other Person who controls the Company (within the meaning of the
         Securities Act) against any Losses, joint or several, to which the
         Company, its directors and officers and each other controlling Person
         may become subject under the Securities Act or otherwise, insofar as
         such Losses (or actions or proceedings, whether commenced or
         threatened, in respect thereof) arise out of or are based upon (i) the
         purchase or sale of Registrable Securities during any period beginning
         upon a Changing Event (as defined in Section 9.4(e)) and ending on a
         Correction Event (as defined in Section 9.4(e)), provided such
                                                          --------
         holder of Registrable Securities received proper written notice of such
         Changing Event pursuant to Section 9.4(e), (ii) any untrue or alleged
         untrue statement of material fact contained in the registration
         statement, prospectus or preliminary prospectus or any amendment or
         supplement thereto, or (iii) any omission or alleged omission of a
         material fact required to be stated therein or necessary to make the
         statements therein not misleading, but, with respect to clauses (ii)
         and (iii) above, only to the extent that such untrue statement or
         omission is made in such registration statement any such prospectus or
         preliminary prospectus or any amendment or supplement thereto, in
         reliance upon and in conformity with written information prepared and
         furnished to the Company by such holder of Registrable Securities
         expressly for use therein, and such holder of Registrable Securities
         will reimburse the Company and each such director, officer and
         controlling Person for any legal or any other expenses incurred by them
         in connection with investigating or defending any such Loss, action or
         proceeding; provided, however, that the obligation to indemnify will be
                     --------  -------
         individual to each such holder of Registrable Securities and will be
         limited to the net amount of proceeds received by such holder of
         Registrable Securities from the sale of Registrable Securities pursuant
         to such registration statement.

     (c) Any Person entitled to indemnification hereunder will (i) give prompt
         written notice to the indemnifying party of any claim with respect to
         which it seeks indemnification (provided that the failure to give
                                         --------
         prompt notice shall not impair any Person's right to indemnification
         hereunder to the extent such failure has not materially prejudiced the
         indemnifying party) and (ii) unless in such indemnified party's
         reasonable judgment a conflict of interest between such indemnified and
         indemnifying parties may exist with respect to such claim, permit such
         indemnifying party to assume the defense of such claim with counsel
         reasonably satisfactory to the indemnified party. Such indemnifying
         party shall not,

                                       17
<PAGE>

          however, enter into any settlement with a party without obtaining an
          unconditional release of each indemnified party by such party with
          respect to any and all claims against each indemnified party. If such
          defense is assumed, the indemnifying party will not be subject to any
          liability for any settlement made by the indemnified party without its
          consent (but such consent will not be unreasonably withheld). An
          indemnifying party who is not entitled to, or elects not to, assume
          the defense of a claim will not be obligated to pay the fees and
          expenses of more than one counsel for all parties indemnified by such
          indemnifying party with respect to such claim, unless in the
          reasonable judgment of any indemnified party a conflict of interest
          may exist between such indemnified party and any other of such
          indemnified parties with respect to such claim.

     (d)  The indemnification provided for under this Agreement will remain in
          full force and effect regardless of any investigation made by or on
          behalf of the indemnified party or any officer, director or
          controlling Person of such indemnified party and will survive the
          transfer of securities. The Company also agrees to make such
          provisions, as are reasonably requested by any indemnified party, for
          contribution to such party in the event the Company's indemnification
          is unavailable for any reason.

     9.7  Participation in Underwritten Registrations.
          -------------------------------------------

     (a)  No Person may participate in any registration hereunder which is
          underwritten unless such Person (i) agrees to sell such Person's
          securities on the basis provided in any underwriting arrangements
          approved by the Person or Persons entitled hereunder to approve such
          arrangements (including, without limitation, pursuant to the terms of
          any over-allotment or "green shoe" option requested by the managing
          underwriter(s), provided that each holder of Registrable Securities
                          --------
          shall not be required to sell more than the number of Registrable
          Securities that such holder has requested the Company to include in
          any registration) and (ii) completes and executes all questionnaires,
          powers of attorney, indemnities, underwriting agreements and other
          documents reasonably required under the terms of such underwriting
          arrangements.

     (b)  Each Person that is participating in any registration hereunder agrees
          that, upon receipt of any notice from the Company of the happening of
          any event of the kind described in Section 9.4(e) above, such Person
          will forthwith discontinue the disposition of its Registrable
          Securities pursuant to the registration statement until such Person's
          receipt of the copies of a supplemented or amended prospectus as
          contemplated by such Section 9.4(e). In the event the Company shall
          give any such notice, the applicable time period mentioned in Section
          9.4(b) during which a Registration Statement is to remain effective
          shall be extended by the number of

                                       18
<PAGE>

          days during the period from and including the date of the giving of
          such notice pursuant to this paragraph to and including the date when
          each seller of a Registrable Security covered by such registration
          statement shall have received the copies of the supplemented or
          amended prospectus contemplated by Section 9.4(e).

     9.8   Current Public Information.  At all times after the Company has filed
           --------------------------
a registration statement with the Securities and Exchange Commission pursuant
to the requirements of either the Securities Act or the Securities Exchange Act,
the Company will file all reports required to be filed by it under the
Securities Act and the Securities Exchange Act and the rules and regulations
adopted by the Securities and Exchange Commission thereunder, and will use
commercially reasonable best efforts to take such further action as the
Purchasers may reasonably request, all to the extent required to enable the
holders of Registrable Securities to sell Registrable Securities pursuant to
Rule 144 adopted by the Securities and Exchange Commission under the Securities
Act (as such rule may be amended from time to time) or any similar rule or
regulation hereafter adopted by the Securities and Exchange Commission.

     9.9   Adjustment Affecting Registrable Securities.  Except as otherwise
           -------------------------------------------
provided herein, the Company will not effect a stock split or dividend or a
combination of shares or take any similar action, or permit any similar change
to occur, with respect to its securities which would materially and adversely
affect the ability of the holders of Registrable Securities to include such
Registrable Securities in a registration undertaken pursuant to this Agreement
or which would adversely affect the marketability of such Registrable Securities
in any such registration (including, without limitation, effecting a stock split
or a combination of shares) in any material respect.

     9.10  Form S-3 Registration.  In case the Company shall receive from the
           ---------------------
Majority Series A/B Holders or the Majority Priority Preferred Holders, a
written request or requests that the Company effect a registration on Form S-3
under the Securities Act (or any similar successor form) and any related
qualification or compliance with respect to all or a part of the Registrable
Securities owned such holders, the Company will:

     (a)   promptly give written notice of the proposed registration, and any
           related qualification or compliance, to all other holders of
           securities of the Company; and

     (b)   as soon as practicable, use its best efforts to effect such
           registration and all such qualifications and compliances as may be so
           requested and as would permit or facilitate the sale and distribution
           of all or such portion of the Registrable Securities as are specified
           in such request, together with all or such portion of the securities
           of any other holder in the group of All Preferred Holders of
           securities joining in such request as is specified in a written
           request given within fifteen (15) days after receipt of such written
           notice from the Company; provided, however,
                                    --------  -------

                                       19
<PAGE>

           that the Company shall not be obligated to effect any such
           registration, qualification or compliance pursuant to this Section
           9.10: (i) if the Company is not qualified as a registrant entitled to
           use Form S-3 (or the applicable successor form); (ii) if the Holders
           of Series A Preferred Stock and Series B Preferred Stock of the
           Company and the holders of the Priority Preferred Shares, together
           with the holders of any other securities of the Company entitled to
           inclusion in such registration, propose to sell Registrable
           Securities and such other securities at an aggregate price to the
           public of less than One Million Dollars ($1,000,000); or (iii) if the
           Company shall furnish to All Preferred Holders that requested to be
           included in such registration, a certificate signed by the President
           of the Company stating that in the good faith judgment of the Board
           of Directors of the Company, it would be seriously detrimental to the
           Company and its shareholders for such Form S-3 registration to be
           effected at such time, in which event the Company shall have the
           right to defer the filing of the Form S-3 registration statement for
           a period of not more than ninety (90) days after receipt of request
           of the Majority Series A/B Holders or the Majority Priority Preferred
           Holders, as the case may be, under this Section 9.10; provided,
                                                                 --------
           however, that the Company shall not utilize this right more than
           -------
           once in any twelve (12) month period.

           Subject to the foregoing, the Company shall file and use its best
efforts to bring effective a registration statement covering the Registrable
Securities and other securities so requested to be registered as soon as
practicable after receipt of the request of either the Majority Series A/B
Holders or the Majority Priority Preferred Holders.

10.  Financial Statements, Reports, Etc.  The Company shall furnish to All
     -----------------------------------
     Preferred Holders:

     (a)   within forty-five (45) days following the Closing Date, the audited
           consolidated balance sheet of the Company and its subsidiaries as of
           December 31, 1998 and the audited consolidated statement of income
           and retained earnings and the audited consolidated statement of cash
           flows of the Company and its subsidiaries, each for the fiscal year
           ended December 31, 1998;

     (b)   as soon as practicable, but in any event within forty-five (45) days
           after the end of each of the first three (3) quarters of each fiscal
           year of the Company, an unaudited balance sheet and income statement
           as of the end of such fiscal quarter, in reasonable detail and
           prepared in accordance with GAAP;

     (c)   as soon as available, and in any event within 90 days after the end
           of each subsequent fiscal year of the Company, (i) an audited
           consolidated financial statement of the Company and its subsidiaries
           as of the end of such fiscal year, together with the related audited
           consolidated statements of income, stockholders' equity and cash
           flows for the fiscal year then ended, prepared in accordance with

                                       20
<PAGE>

           GAAP and certified by a "Big 5" firm of independent public
           accountants selected by the board of directors of the Company (the
           "Board") (the "Annual Financial Statement"); and (ii) any related
           management letters from such accounting firm. The Annual Financial
           Statement shall be accompanied by comparative statements from the
           prior fiscal year and the most recent 12-month budget delivered by
           the Company pursuant to Section 10(d) hereof;

     (d)   as soon as available after the end of each month in each fiscal year
           (other than the last month in each fiscal year) a monthly, unaudited
           consolidated balance sheet of the Company and its subsidiaries and
           the related unaudited consolidated statements of income,
           stockholders' equity and cash flows (the "Monthly Balance Sheet").
           The Company will furnish the Monthly Balance Sheet within 20 days
           after the end of each such month. The Monthly Balance Sheet shall be
           accompanied by a monthly management report describing the current
           status of the Company and its operations and prospects. The Monthly
           Balance Sheet should be prepared as of the end of such month with
           statements of income, stockholders' equity and cash flows to be for
           such month and for the period from the beginning of the fiscal year
           to the end of such month, in each case with comparative statements
           for the prior fiscal year and the most recent 12-month budget
           delivered by the Company pursuant to Section 10(d) hereof, and which
           shall specifically note and describe all expenditures (in any single
           transaction or series of related transactions) in excess of $50,000
           not included in the most recent 12-month budget delivered by the
           Company pursuant to Section 10(d) hereof;

     (e)   as soon as available, and in any event no later than 15 days prior to
           the start of each fiscal year, capital and operating expense budget,
           cash flow projections and income and loss projections for the Company
           in respect of such fiscal year, all itemized in reasonable detail and
           prepared on a monthly basis, and, promptly after preparation, any
           revisions to any of the foregoing;

     (f)   promptly, notice, and in any event within five days after notice has
           been received by the Company, of any material adverse event, claim,
           dispute or any other development which is material to operations,
           assets or properties of the Company;

     (g)   promptly, from time to time, such other information regarding the
           business, prospects, financial condition, operations, property or
           affairs of the Company that All Preferred Holders may reasonably
           request; provided, that if such other information is not so provided,
                    --------
           All Preferred Holders and their Representatives shall be entitled,
           upon reasonable notice, and at their own expense, to make such
           investigation of the properties, business and operations of the
           Company and such examination of the books, records and financial
           condition of the Company as they reasonably request and to make
           extracts and copies of such books and records.

                                       21
<PAGE>

           Any such investigation and examination shall be conducted during
           regular business hours and under reasonable circumstances without
           material interference with the Company's normal business operations,
           and the Company and its Representatives shall cooperate fully
           therein.

11.  Additional Covenants.
     --------------------

     (a)   Subject to the execution of such confidentiality agreement as may be
           reasonably required by the Company, Weiss, Peck & Greer Venture
           Partners shall have the right to attend meetings of the Board;

     (b)   The Company agrees that to the extent permitted by law, all Common
           Stock issued to Employees subsequent to the date of this Agreement
           shall be subject to a repurchase option which provides that upon
           termination of the employment of such individual, with or without
           cause, the Company has the option to repurchase at cost any unvested
           shares held by the individual, which repurchase option shall lapse
           over four (4) years with twenty-five percent (25%) to vest at the end
           of the first year following the vesting commencement date, with the
           remaining seventy-five percent (75%) to vest monthly over the three
           (3) years thereafter, unless otherwise determined unanimously by the
           Board; provided, however, that shares issued pursuant to a stock
                  --------  -------
           option plan or arrangement shall have similarly applicable vesting
           provisions such that unvested shares shall revert to the Company
           under any applicable stock option plan or arrangement.

12.  Termination of Rights and Obligations.  The rights and obligations of the
     -------------------------------------
     holders of Priority Preferred Shares set forth in this Agreement, except
     rights and obligations under Section 4, shall terminate in the event that
     the holders of Priority Preferred Shares and/or their Permitted Transferees
     do not own at least five percent (5%) of the Fully Diluted Common Stock.
     The rights and obligations of the Series A Holders or the Series B Holders,
     as the case may be, set forth in this Agreement, except rights and
     obligations under Section 4, shall terminate in the event that the Series A
     Holders and their Permitted Transferees or the Series B Holders and their
     Permitted Transferees, as the case may be, do not own at least five percent
     (5%) of the Fully Diluted Common Stock.  The rights and obligations of the
     Founders set forth in this Agreement, except rights and obligations under
     Section 4, shall terminate in the event the Founders and their Permitted
     Transferees cease to own in the aggregate at least five percent (5%) of the
     Fully Diluted Common Stock.  Any such termination of the rights and
     obligations of any party shall not affect the rights and obligations of the
     remaining parties.  In addition, the preemptive rights provided in Section
     6 shall terminate upon the consummation of a Qualifying IPO and the
     covenants set forth in Section 11 shall terminate upon the earlier to occur
     of (i) the effective date of a Qualifying IPO and (ii) the date on which
     the Company first becomes

                                       22
<PAGE>

     subject to the periodic reporting requirements of Section 12(g) or 15(d) of
     the Securities Exchange Act of 1934.

13.  Rights Regarding Issuance of Priority Preferred Shares.   Except for the
     ------------------------------------------------------
     purchase by the Series A Holders and Series B Holders of Series C Stock and
     its right to purchase up to Eight Million Dollars ($8,000,000) of Series D
     Stock in each case as provided in the Securities Purchase Agreement, the
     Series A and Series B Holders hereby waive any other rights they may have
     to purchase Priority Preferred Shares, including, without limitation, any
     right of first offer or preemptive rights; provided, however, nothing
                                                --------  -------
     herein shall preclude the Series A Holders and the Series B Holders from
     purchasing additional shares of Series D Stock in the event that Baker does
     not exercise the Baker Option.

14.  Grant of Proxy.  Should Section 1 of this Agreement be construed to
     --------------
     constitute the granting of proxies with respect to the election of
     directors, such proxies shall be deemed coupled with an interest and are
     irrevocable for the term of this Agreement.

15.  Specific Enforcement.  It is agreed and understood that monetary damages
     --------------------
     would not adequately compensate an injured party for the breach of this
     Agreement by any other party to this Agreement, that this Agreement shall
     be specifically enforceable, and that any breach of this Agreement shall be
     the proper subject of a temporary or permanent injunction or restraining
     order.  Each party hereto waives any claim or defense that there is an
     adequate remedy at law for such breach or threatened breach.

16.  Stock Splits, Stock Dividends, etc.  In the event of any stock split, stock
     -----------------------------------
     dividend, recapitalization, reorganization or combination, any securities
     issued to the parties shall be subject to this Agreement.

17.  Merger.  This Agreement supersedes, merges and renders void any and all
     ------
     prior agreements and/or understandings among or between the parties, oral
     or written, with respect to its subject matter including the Investor
     Rights Agreement, dated as of January 29, 1998, by and among the Company
     and each of the persons who purchased shares of Series A Preferred Stock of
     the Company (the "Series A Purchasers"), as amended by Amendment No. 1
     dated as of September 9, 1998; the Co-Sale and Right of First Refusal
     Agreement, dated as of January 29, 1998 by and among the Company, the
     Founders and each of the Series A Purchasers; and the Voting Agreement,
     dated as of January 29, 1998, by and among the Company, the Founders and
     each of the Series A Purchasers.

18.  Manner of Voting.  The voting of shares pursuant to this Agreement may be
     ----------------
     effected in person, by proxy, by written consent, or in any other manner
     permitted by applicable law.

                                       23
<PAGE>

19.  Term.  This Agreement shall continue in full force and effect for a period
     ----
     of ten (10) years commencing from the date of this Agreement.

20.  Miscellaneous.  Any reference in this Agreement to a requirement for a
     -------------
     request by a majority in interest or seventy-five percent (75%) of a class
     of preferred stock of the Company shall be deemed to include any Common
     Stock into which such series of preferred stock has been converted.

21.  Certain Definitions.  The following capitalized terms shall have the
     -------------------
     meanings ascribed to them below:

          "Affiliate" means any Person that directly or indirectly controls, or
          is under control with, or is controlled by such Person. As used in
          this definition, "control" (including with its correlative meanings,
          "controlled by" and "under common control with") shall mean the
          possession, directly or indirectly, of the power to direct or cause
          the direction of the management or policies of a Person (whether
          through ownership of securities or partnership or other ownership
          interests, by contract or otherwise).

          "Common Stock" means the common stock, $0.01 par value per share, of
          the Company.

          "Employees" means any current, former, or retired employee, office
          consultant, advisor, independent contractor, agent, officer or
          director of the Company.

          "Fully Diluted Common Stock" means, at any given time, all shares of
          Common Stock issued and outstanding at such time, plus all shares of
          Common Stock then issuable upon exercise of any then outstanding
          options and convertible securities of the Company, whether or not such
          options or convertible securities are actually exercisable or
          convertible at such time.

          "Permitted Transferee" means in the case of each of the parties to
          this Agreement, and upon the condition that such transferee becomes a
          party to this Agreement, (i) a Person to whom securities of the
          Company are transferred from such transferring party by will or the
          laws of descent and distribution or by gift without consideration of
          any kind; provided that such transferee is the issue, adopted issue,
                    --------
          stepchild, parent or spouse of such transferring party, (ii) a trust
          that is for the exclusive benefit of, or a partnership the partners of
          which are exclusively, such transferring party or his or her Permitted
          Transferees under (i) above, (iii) the transfer of securities to an
          Affiliate, (iv) a Person to whom securities of the Company are
          transferred pursuant to (a) a public offering registered under the
          Securities Act of 1933, as amended, or (b) a merger, sale,
          consolidation,

                                       24
<PAGE>

          reorganization or recapitalization or other business combination with,
          to, or into one or more third parties which (1) has been approved by
          the Board of the Company and a majority of its outstanding shares in
          accordance with New York law and (2) after such event the Company is
          not the surviving entity or the shareholders of the Company do not own
          a majority in interest of the resulting entity, or (v) a Person to
          whom securities of the Company are transferred with the consent of the
          other parties. A Permitted Transferee shall also include, upon the
          condition that such transferee becomes a party to this Agreement, the
          transfer of securities from (i) one Founder to another Founder, (ii)
          one Series A Holder to another Series A Holder, (iii) one Series B
          Holder to another Series B Holder, and (iv) one holder of Priority
          Preferred Shares to an officer or principal of such holder.

          "Person" means any individual, corporation, partnership, firm, joint
          venture, association, joint-stock company, trust, unincorporated
          organization, governmental body or other entity.

          "Registrable Securities" means (i) any shares of Common Stock issued
          or issuable upon conversion of the Priority Preferred Shares held by
          Baker or the Holders, (ii) any shares of Common Stock issued or
          issuable upon conversion of the Series A Preferred Stock or the Series
          B Preferred Stock of the Company held by the Holders, (iii) any other
          shares of Common Stock held by the holders in clauses (i) and (ii),
          and (iv) any shares of Common Stock issued or issuable directly or
          indirectly with respect to the securities referred to in clauses (i)
          through (iii) by way of stock dividend or stock split or in connection
          with a combination of shares, recapitalization, merger, consolidation
          or other reorganization. As to any particular shares constituting
          Registrable Securities, such shares will cease to be Registrable
          Securities when they have been (x) effectively registered under the
          Securities Act and disposed of in accordance with a registration
          statement covering them or (y) sold to the public pursuant to Rule 144
          (or by similar provision under the Securities Act).

          "Qualifying IPO" as defined in the Certificate of Designation,
          Preferences and Rights of the Series C Stock.

          "Year 2000 Problem" means (i) any material error relating to or
          resulting from date data which represents or references more than one
          century ("Century-Based Data"); (ii) any abnormal ending or provision
          of materially invalid or incorrect results as a result of any Century-
          Based Data; or (iii) any material error relating to century
          recognition or calculations accommodating Century-Based Data, values
          or formulae, and the implementation of such plan is expected in good
          faith to be completed in a timely manner.

                                       25
<PAGE>

22.  Severability.  Whenever possible, each provision of this Agreement shall be
     ------------
     interpreted in such manner as to be effective and valid under applicable
     law, but if any provision of this Agreement shall be held to be prohibited
     by or invalid under applicable law, such provision shall be ineffective
     only to the extent of such prohibition or invalidity, without invalidating
     the remainder of such provision or the remaining provisions of this
     Agreement.

23.  Counterparts.  This Agreement may be executed in one or more counterparts
     ------------
     each of which shall be deemed an original, but all of which together shall
     constitute one and the same instrument.

24.  Notices.  Any notice required or permitted by this Agreement shall be in
     -------
     writing and shall be deemed given when delivered personally, by telecopy or
     mailed by certified mail, return receipt requested, to the parties at the
     addresses opposite their signature or at such other address as a party may
     specify by giving notice to the other parties pursuant to this Section 24.

25.  Governing Law.  This Agreement shall be governed by and construed in
     -------------
     accordance with the laws of the State of New York, without regard to the
     conflicts of laws rules or provisions.

26.  Consent to Jurisdiction.
     -----------------------

     (a)  The parties hereto hereby irrevocably submit to the non-exclusive
          jurisdiction of any federal or state court located within the Borough
          of Manhattan, State of New York over any dispute arising out of or
          relating to this Agreement or any of the transactions contemplated
          hereby and each party hereby irrevocably agrees that all claims in
          respect of such dispute or any suit, action or proceeding related
          thereto may be heard and determined in such courts. The parties hereby
          irrevocably waive, to the fullest extent permitted by applicable law,
          any objection which they may now or hereafter have to the laying of
          venue of any such dispute brought in such court or any defense of
          inconvenient forum for the maintenance of such dispute. Each of the
          parties hereto agrees that a judgment in any such dispute may be
          enforced in other jurisdictions by suit on the judgment or in any
          other manner provided by law.

     (b)  Each of the parties hereto hereby consents to process being served by
          any party to this Agreement in any suit, action or proceeding by the
          mailing of a copy thereof in accordance with the provisions of Section
          24 hereof.

27.  Assignees and Transferees.  This Agreement shall be binding upon and inure
     -------------------------
     to the benefit of the parties and their respective successors and permitted
     assigns.  The parties

                                       26
<PAGE>

     hereby agree that any transfer or assignment of voting securities of the
     Company to a Permitted Transferee is conditioned upon such Permitted
     Transferee's execution and delivery of this Agreement prior to such
     transfer or assignment for the purpose of becoming a party to this
     Agreement. The Company hereby agrees that any transfer or assignment of its
     voting securities is conditioned upon such transferee's or assignee's
     execution and delivery of this Agreement prior to such transfer or
     assignment for the purpose of becoming a party to this Agreement.

28.  Captions.  The captions, headings and arrangements used in this Agreement
     --------
     are for convenience only and do not in any way limit or amplify the terms
     and provisions hereof.

                                       27
<PAGE>

     IN WITNESS WHEREOF, the parties have executed this Agreement as of the date
first written above.

                              COAXICOM, INC.

                              By: /s/ Vern Kennedy
                                  --------------------------------
                                   Name:  Vern Kennedy
                                   Title: President and CEO
<PAGE>

                              BAKER COMMUNICATIONS FUND, L.P.,

                              By: Baker Capital Partners, LLC
                                  Its General Partner

                              By: /s/ Edward Scott
                                  --------------------------------
                                  Name: Edward Scott
                                  Title:Manager

                              COMMUNICATIONS VENTURES II, L.P.

                              By: /s/ Roland A. Van der Meer
                                  --------------------------------
                                  Name: Roland A. Van der Meer
                                  Title:Managing Member

                              COMMUNICATIONS VENTURES II
                              AFFILIATES FUND, L.P.

                              By: /s/ Roland A. Van der Meer
                                  --------------------------------
                                  Name: Roland A. Van der Meer
                                  Title:Managing Member

                              NEW ENTERPRISE ASSOCIATES VII, L.P.

                              By: NEA Partners VII, L.P.,
                                  General Partner

                              By: /s/ Nancy Dorman
                                  --------------------------------
                                  Name: Nancy Dorman
                                  Title:

                     Shareholder Agreement Signature Page
<PAGE>

                              NEA PRESIDENTS FUND

                              By: /s/ Nancy Dorman
                                  ---------------------------------
                                  Name: Nancy Dorman
                                  Title:General Partner

                              NEA VENTURES 1998, L.P.

                              By: /s/ Nancy Dorman
                                  ---------------------------------
                                  Name: Nancy Dorman
                                  Title:Vice President

                              WPG ENTERPRISE FUND III, L.L.C.

                              By: WPG VC Fund Adviser, L.L.C.,
                                  Fund Investment Advisory Member

                              By: /s/ Barry Eggers
                                  ---------------------------------
                                  Name: Barry Eggers
                                  Title:Managing Member

                              WEISS, PECK & GREER VENTURE
                              ASSOCIATES IV, L.L.C.

                              By: WPG VC Fund Adviser, L.L.C.,
                                  Fund Investment Advisory Member

                              By: /s/ Barry Eggers
                                  ---------------------------------
                                  Name: Barry Eggers
                                  Title:Managing Member

                     Shareholder Agreement Signature Page
<PAGE>

                              WPG INFORMATION SCIENCES
                              ENTREPRENEUR FUND, L.P.

                              By: WPG VC Fund Adviser, L.L.C.,
                                  General Partner

                              By: /s/ Barry Eggers
                                  ----------------------------------
                                  Name: Barry Eggers
                                  Title:Managing Member

                     Shareholder Agreement Signature Page
<PAGE>

                              WEISS, PECK & GREER VENTURE
                              ASSOCIATES IV CAYMAN, L.P.

                              By: WPG Venture Advisers, Ltd.
                                  Administrative General Partner

                              By: /s/ Scott Dakers
                                  --------------------------------
                                  Name: Scott Dakers
                                  Title:Director

                     Shareholder Agreement Signature Page
<PAGE>

                              /s/ Vern M. Kennedy
                              ------------------------------
                              Vern M. Kennedy

                              /s/ Terrence J. Anderson
                              ------------------------------
                              Terrence J. Anderson

                              /s/ Philip B. Smith
                              ------------------------------
                              Philip B. Smith

                              /s/ Tracy W. Korman
                              ------------------------------
                              Tracy W. Korman

                     Shareholder Agreement Signature Page

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