<PAGE>

                                                                     EXHIBIT 4.2


                         REGISTRATION RIGHTS AGREEMENT
                         -----------------------------

    This Registration Rights Agreement is made and entered into as of September
27, 1999, by and between VerticalNet, Inc., a Pennsylvania corporation (the
"Company"), and Lehman Brothers Inc., Hambrecht & Quist LLC, SG Cowen Securities
Corporation and Volpe Brown Whelan & Company LLC (the "Initial Purchasers") who
has purchased or has the right to purchase up to $100,000,000 (up to
$115,000,000 if the over-allotment option is exercised) in aggregate principal
amount of 5 1/4% Convertible Subordinated Debentures due 2004 (the "Debentures")
of the Company pursuant to the Purchase Agreement (as such term is defined
below).

    This Agreement is made pursuant to the Purchase Agreement, dated September
21, 1999, between the Company and the Initial Purchasers (the "Purchase
Agreement").  In order to induce the Initial Purchasers to enter into the
Purchase Agreement, the Company has agreed to provide the registration rights
provided for in this Agreement to the Initial Purchasers and its respective
direct and indirect transferees (i) for the benefit of the Initial Purchasers,
(ii) for the benefit of the holders from time to time of the Debentures
(including the Initial Purchasers) and the holders from time to time of the
Common Stock issuable or issued upon conversion of the Debentures and (iii) for
the benefit of the securities constituting the Transfer Restricted Securities
(as defined below).  The execution of this Agreement is a condition to the
closing of the transactions contemplated by the Purchase Agreement.

        The parties hereby agree as follows:

    1.  Definitions.  As used in this Agreement, the following terms shall have
        -----------
the following meanings:

    Advice:  As defined in Section 2(d) hereof.
    ------

    Affiliate:  An affiliate of any specified person shall mean any other person
    ---------
directly or indirectly controlling or controlled by or under direct or indirect
common control with such specified person.  For the purposes of this definition,
"control," when used with respect to any person, means the power to direct the
management and policies of such person, directly or indirectly, whether through
the ownership of voting securities, by contract or otherwise and the terms
"affiliated," "controlling" and "controlled" have meanings correlative to the
foregoing.

    Agreement:  This Registration Rights Agreement, as the same may be amended,
    ---------
supplemented or modified from time to time in accordance with the terms hereof.
<PAGE>

    Business Day:  Each Monday, Tuesday, Wednesday, Thursday and Friday that is
    ------------
not a day on which banking institutions in New York, New York are authorized or
obligated by law or executive order to close.

    Closing Date:  September 27, 1999.
    ------------

    Common Stock:  common stock, $0.01 par value per share, of the Company and
    ------------
any other shares of common stock as may constitute "Common Stock" for purposes
of the Indenture, in each case, as issuable or issued upon conversion of the
Debentures.

    Company:  VerticalNet, Inc., a Pennsylvania corporation, and any successor
    -------
corporation thereto.

    controlling person:  As defined in Section 6(a) hereof.
    ------------------

    Debentures:  The $100,000,000 aggregate principal amount of 5 1/4%
    ----------
Convertible Subordinated Debentures due 2004 of the Company being issued
pursuant to the Indenture (up to $115,000,000 aggregate principal amount of such
Debentures if, and to the extent, the Initial Purchasers' over-allotment option
is exercised).

    Effectiveness Period:  As defined in Section 2(a) hereof.
    --------------------

    Effectiveness Target Date:  The 225th day following the Closing Date.
    -------------------------

    Exchange Act:  The Securities Exchange Act of 1934, as amended, and the
    ------------
rules and regulations promulgated by the SEC pursuant thereto.

    Filing Date:  The 150th day after the Closing Date.
    -----------

    Holder:  Each owner of any Transfer Restricted Securities.
    ------

    Indemnified Person:  As defined in Section 6(a) hereof.
    ------------------

    Indenture:  The Indenture, dated as of the date hereof, between the Company
    ---------
and the Trustee thereunder, pursuant to which the Debentures are being issued,
as amended, modified or supplemented from time to time in accordance with the
terms thereof.

    Initial Purchasers:  As defined in the first paragraph hereof.
    ------------------

    Liquidated Damages:  As defined in Section 3 hereof.
    ------------------

                                       2
<PAGE>

    Proceeding:  An action, claim, suit or proceeding (including, without
    ----------
limitation, an investigation or partial proceeding, such as disposition),
whether commenced or threatened.

    Prospectus:  The prospectus included in any Registration Statement
    ----------
(including, without limitation, a prospectus that discloses information
previously omitted from a prospectus filed as part of an effective registration
statement in reliance upon Rule 430A promulgated pursuant to the Securities
Act), as amended or supplemented by any prospectus supplement, with respect to
the resale of any of the Transfer Restricted Securities covered by such
Registration Statement, and all other amendments and supplements to any such
prospectus, including post-effective amendments, and all materials incorporated
by reference or deemed to be incorporated by reference, if any, in such
prospectus.

    Purchase Agreement:  As defined in the second paragraph hereof.
    ------------------

    Registration Statement:  Any registration statement of the Company filed
    ----------------------
with the SEC pursuant to the Securities Act that covers the resale of any of the
Transfer Restricted Securities pursuant to the provisions of this Agreement,
including the Prospectus, amendments and supplements to such registration
statement or Prospectus, including pre- and post-effective amendments, all
exhibits thereto, and all material incorporated by reference or deemed to be
incorporated by reference, if any, in such registration statement.

    Rule 144:  Rule 144 promulgated by the SEC pursuant to the Securities Act,
    --------
as such Rule may be amended from time to time, or any successor rule or
regulation.

    Rule 144A:  Rule 144A promulgated by the SEC pursuant to the Securities Act,
    ---------
as such Rule may be amended from time to time, or any successor rule or
regulation.

    Rule 158:  Rule 158 promulgated by the SEC pursuant to the Securities Act,
    --------
as such Rule may be amended from time to time, or any successor rule or
regulation.

    Rule 174:  Rule 174 promulgated by the SEC pursuant to the Securities Act,
    --------
as such Rule may be amended from time to time, or any successor rule or
regulation.

    Rule 415:  Rule 415 promulgated by the SEC pursuant to the Securities Act,
    --------
as such Rule may be amended from time to time, or any successor rule or
regulation.

    Rule 424:  Rule 424 promulgated by the SEC pursuant to the Securities Act,
    --------
as such Rule may be amended from time to time, or any successor rule or
regulation.

                                       3
<PAGE>

    Sale Notice:  As defined in Section 2(d) hereof.
    -----------

    SEC:  The Securities and Exchange Commission.
    ---

    Securities Act:  The Securities Act of 1933, as amended, and the rules and
    --------------
regulations promulgated by the SEC thereunder.

    Shelf Registration Statement:  As defined in Section 2(a) hereof.
    ----------------------------

    Special Counsel:  Any special counsel to the holders of Transfer Restricted
    ---------------
Securities.

    TIA:  The Trust Indenture Act of 1939, as amended.
    ---

    Transfer Restricted Securities:  The Debentures and the shares of Common
    ------------------------------
Stock into which the Debentures are converted or convertible (including any
shares of Common Stock issued or issuable thereon upon any stock split, stock
combination, stock dividend or the like), upon original issuance thereof, and at
all times subsequent thereto, and associated related rights, if any, until, in
the case of any such Debenture or share (and associated rights) (i) the date on
which the resale thereof has been registered effectively pursuant to the
Securities Act and have been disposed of in accordance with the Registration
Statement relating thereto, (ii) the date on which either such Debenture or the
shares of Common Stock issued upon conversion of such Debenture are distributed
to the public pursuant to Rule 144 (or any similar provisions then in effect) or
are saleable pursuant to Rule 144(k) promulgated by the SEC pursuant to the
Securities Act or (iii) the date on which it ceases to be outstanding, whichever
date is earliest.

    Trustee:  The Trustee under the Indenture.
    -------

    Underwritten registration or underwritten offering:  A registration in
    --------------------------------------------------
connection with which securities of the Company are sold to an underwriter for
reoffering to the public pursuant to an effective Registration Statement.

    References herein to the term "Holders of a majority in aggregate principal
amount of Transfer Restricted Securities" or words to a similar effect shall
mean, with respect to any request, notice, demand, objection or other action by
the holders of Transfer Restricted Securities hereunder or pursuant hereto
(each, an "Act"), registered holders of a number of shares of then outstanding
Common Stock constituting Transfer Restricted Securities and an aggregate
principal amount of then outstanding Debentures constituting Transfer Restricted
Securities, such that the sum of such shares of Common Stock and the shares of
Common Stock issuable upon conversion of such Debentures constitute in

                                       4
<PAGE>

excess of 50% of the sum of all of the then outstanding shares of Common Stock
constituting Transfer Restricted Securities and the number of shares of Common
Stock issuable upon conversion of then outstanding Debentures constituting
Transfer Restricted Securities. For purposes of the immediately preceding
sentence, (i) any Holder may elect to take any Act with respect to all or any
portion of Transfer Restricted Securities held by it and only the portion as to
which such Act is taken shall be included in the numerator of the fraction
described in the preceding sentence and (ii) Transfer Restricted Securities
owned, directly or indirectly, by the Company or its Affiliates shall be deemed
not to be outstanding.

    2.  Shelf Registration Statement.  (a)  The Company agrees to file with the
        ----------------------------
SEC as soon as practicable after the Closing Date, but in no event later than
the Filing Date, a Registration Statement for an offering to be made on a
continuous basis pursuant to Rule 415 covering all of the Transfer Restricted
Securities (the "Shelf Registration Statement").  The Shelf Registration
Statement shall be on Form S-3 under the Securities Act or another appropriate
form selected by the Company permitting registration of such Transfer Restricted
Securities for resale by the Holders in the manner or manners reasonably
designated by them (including, without limitation, one or more underwritten
offerings).  The Company shall not permit any securities other than the Transfer
Restricted Securities to be included in the Shelf Registration Statement.  The
Company shall use all reasonable efforts to cause the Shelf Registration
Statement to be declared effective pursuant to the Securities Act as promptly as
practicable following the filing thereof, but in no event later than the
Effectiveness Target Date, and to keep the Shelf Registration Statement
continuously effective under the Securities Act until the date that is 24 months
after the date on which all of the Debentures are sold (including those sold
pursuant to the over-allotment option granted to the Initial Purchasers in the
Purchase Agreement) to the Initial Purchasers (the "Effectiveness Period"), or
such shorter period ending when there cease to be outstanding any Transfer
Restricted Securities.

    (b) Supplements and Amendments.  Subject to Section 2(d) hereof, the Company
        --------------------------
shall use its reasonable efforts to keep the Shelf Registration Statement
continuously effective by supplementing and amending the Shelf Registration
Statement if required by the rules, regulations or instructions applicable to
the registration form used for such Shelf Registration Statement, if required by
the Securities Act, or if reasonably requested by the Holders of a majority in
aggregate principal amount, in the case of the Debentures, or the number, in the
case of the Common Stock, of the Transfer Restricted Securities being sold in
connection with this offering or by any underwriter of such Transfer Restricted
Securities.

                                       5
<PAGE>

    (c) Selling Securityholder Information.  The Company may require each Holder
        ----------------------------------
of Transfer Restricted Securities to be sold pursuant to the Shelf Registration
Statement to furnish to the Company such information regarding the Holder and
the distribution of the Transfer Restricted Securities as the Company may from
time to time reasonably require for inclusion in the Shelf Registration
Statement, and the Company may exclude from such registration the Transfer
Restricted Securities of any Holder that fails to furnish such information
within a reasonable time after receiving such request.  Each Holder of Transfer
Restricted Securities to be sold pursuant to a Shelf Registration Statement
agrees to furnish to the Company all information required to be disclosed in
order to make the information previously furnished to the Company by such Holder
not misleading.

    (d) Certain Notices; Suspension of Sales.  Each Holder of Transfer
        ------------------------------------
Restricted Securities agrees by its acquisition of such Transfer Restricted
Securities to notify the Company (a "Sale Notice") not later than three (3)
Business Days prior to any proposed sale by such Holder of Transfer Restricted
Securities pursuant to the Shelf Registration Statement, which notice shall be
effective for five (5) Business Days.  The Company may, upon written notice to
such Holder, suspend such Holder's use of the Prospectus (which is a part of the
Shelf Registration Statement) for a reasonable period not to exceed (i) forty-
five (45) days or (ii) sixty (60) days in the event of or relating to public
filings with the SEC, a pending financing, acquisition, corporate reorganization
or any other material corporate development of the Company (or would require
premature disclosure thereof), if the Company in its reasonable judgment
believes it may possess material non-public information the disclosure of which
in its reasonable judgment would have a material adverse effect on the Company
and its subsidiaries taken as a whole.  Each Holder of Transfer Restricted
Securities agrees by its acquisition of such Transfer Restricted Securities to
hold any communication by the Company in response to a Sale Notice in
confidence.  Each Holder of Transfer Restricted Securities further agrees by its
acquisition of such Transfer Restricted Securities that, upon receipt of any
notice from the Company of the happening of any event of the kind described in
Section 4(c)(ii), 4(c)(iii), 4(c)(v) or 4(c)(vi) hereof, such Holder will
forthwith discontinue disposition of such Transfer Restricted Securities covered
by such Registration Statement or Prospectus (other than in lawful transactions
exempt from the registration requirements under the Securities Act) until such
Holder's receipt of the copies of the supplemented or amended Prospectus
contemplated by Section 4(j) hereof, or until it is advised in writing (the
"Advice") by the Company that the use of the applicable Prospectus may be
resumed, and, in either case, has received copies of any additional or
supplemental filings that are incorporated or deemed to be incorporated by
reference in such Prospectus.

                                       6
<PAGE>

    (e) Compliance.  The Company shall cause the Shelf Registration Statement
        ----------
and the Prospectus and any amendment or supplement thereto, as of the effective
date of the Shelf Registration Statement, amendment or supplement, (i) to comply
as to form in all material respects with the applicable requirements of the
Securities Act and the rules and regulations of the SEC and (ii) not to contain
any untrue statement of a material fact or omit to state a material fact
required to be stated therein or necessary in order to make the statements
therein, in the light of the circumstances under which they were made, not
misleading.

    3.  Liquidated Damages.  If (a) the Shelf Registration Statement is not
        ------------------
filed with the SEC on or prior to the Filing Date or (b) the Shelf Registration
Statement has not been declared effective by the SEC on or prior to the
Effectiveness Target Date (each such event referred to in clauses (a) and (b), a
"Registration Default"), then the Company will pay to each Holder who has
delivered the information called for in Section 2(c), for the first 90-day
period immediately following the occurrence of such Registration Default,
liquidated damages ("Liquidated Damages") in an amount equal to one-quarter of
one percent (0.25%) per annum times the principal amount of the Transfer
Restricted Securities held by such Holder for so long as the Registration
Default continues.  The amount of Liquidated Damages payable to each Holder
shall increase by an additional one-quarter of one percent (0.25%) per annum
times the principal amount of Transfer Restricted Securities held by such Holder
from and after the 91st day following such Registration Default; provided,
                                                                 --------
however, that (1) upon filing of the Shelf Registration Statement, in the case
-------
of (a) above, or (2) upon the effectiveness of the Shelf Registration Statement,
in the case of (b) above, the Liquidated Damages payable with respect to such
Transfer Restricted Securities as a result of such clause (a) or (b), as
applicable, shall cease; and, provided, further, that the amount of Liquidated
                              --------  -------
Damages shall never exceed one-half of one percent (0.5%) per annum.

    Liquidated Damages shall be paid semi-annually in arrears, with the first
semi-annual payment due on the first interest payment date, as applicable,
following the date on which such Liquidated Damages begin to accrue, and shall
be paid to holders of record of such Transfer Restricted Securities on such
interest payment date in the same manner as interest is paid under the
Indenture.  The payment of any such Liquidated Damages shall in all respects be
subject to the terms and conditions set forth in the Indenture, including,
without limitation, the subordination provisions thereof.  All obligations of
the Company set forth in the preceding paragraph that are outstanding with
respect to any Transfer Restricted Security at the time such security ceases to
be a Transfer Restricted Security shall survive until such time as all such
obligations with respect to such security shall have been satisfied in full.

                                       7
<PAGE>

    4.  Registration Procedures.  In connection with the Company's registration
        -----------------------
obligations hereunder, the Company shall effect such registrations on the
appropriate form selected by the Company available for the sale of the Transfer
Restricted Securities to permit the sale of Transfer Restricted Securities in
accordance with the intended method or methods of disposition thereof, and
pursuant thereto the Company shall as expeditiously as possible:

    (a) No fewer than five Business Days prior to the initial filing of a
Registration Statement or Prospectus and no fewer than two Business Days prior
to the filing of any amendment or supplement thereto (including any document
that would be incorporated or deemed to be incorporated therein by reference),
furnish to the registered (as of the most recent reasonably practicable date
which shall not be more than two Business Days prior to the date such notice is
personally delivered, delivered to a next-day courier, deposited in the mail or
telecopied, as the case may be) Holders of the Transfer Restricted Securities,
Special Counsel and the managing underwriters, if any, copies of all such
documents proposed to be filed, which documents (including those incorporated or
deemed to be incorporated by reference) will be subject to the review of such
Holders, Special Counsel and such underwriters, if any, and cause the officers
and directors of the Company, counsel to the Company and independent certified
public accountants to the Company to respond to such inquiries as shall be
necessary in connection with such Registration Statement, in the opinion of
respective counsel to such Holders and such underwriters, to conduct a
reasonable investigation within the meaning of the Securities Act.  The Company
shall not file any such Registration Statement or related Prospectus or any
amendments or supplements thereto to which the Holders of a majority in
aggregate principal amount, in the case of the Debentures, or the number, in the
case of the Common Stock, of the Transfer Restricted Securities being sold in
connection with this offering, Special Counsel, or the managing underwriters, if
any, shall reasonably object on a timely basis;

    (b) Subject to Section 2(d) hereof, prepare and file with the SEC such
amendments, including post-effective amendments, to each Registration Statement
as may be necessary to keep such Registration Statement continuously effective
for the applicable time period set forth in Section 2(a) hereof; and cause the
related Prospectus to be supplemented by any required Prospectus supplement, and
as so supplemented to be filed pursuant to Rule 424 (or any similar provisions
then in force) under the Securities Act and the Exchange Act with respect to the
disposition of all securities covered by such Registration Statement during such
period in accordance with the intended methods of disposition by the sellers
thereof set forth in such Registration Statement as so amended or in such
Prospectus as so supplemented;

                                       8
<PAGE>

    (c) Notify the registered (as of the most recent reasonably practicable date
which shall not be more than two Business Days prior to the date such notice is
personally delivered, delivered to a next-day courier, deposited in the mail or
telecopied, as the case may be) Holders of Transfer Restricted Securities to be
sold or Special Counsel and the managing underwriters, if any, promptly (and in
the case of an event specified by clause (i)(A) of this paragraph in no event
fewer than two Business Days prior to such filing), and (if requested by any
such person), confirm such notice in writing, (i)(A) when a Prospectus or any
Prospectus supplement or post-effective amendment is proposed to be filed, and,
(B) with respect to a Registration Statement or any post-effective amendment,
when the same has become effective, (ii) of any request of the SEC or any other
Federal or state governmental authority for amendments or supplements to a
Registration Statement or related Prospectus or for additional information
related thereto, (iii) of the issuance by the SEC, any state securities
commission, any other governmental agency or any court of any stop order, order
or injunction suspending or enjoining the use or the effectiveness of a
Registration Statement or the initiation of any proceedings for that purpose,
(iv) if at any time any of the representations and warranties of the Company
contained in any agreement (including any underwriting agreement) contemplated
by Section 4(l) hereof are not true and correct in all material respects, (v) of
the receipt by the Company of any notification with respect to the suspension of
the qualification or exemption from qualification of any of the Transfer
Restricted Securities for sale in any jurisdiction, or the initiation or
threatening of any proceeding for such purpose, and (vi) of the existence of any
fact and the happening of any event that makes any statement made in such
Registration Statement or related Prospectus untrue in any material respect, or
that requires the making of any changes in such Registration Statement or
Prospectus so that in the case of the Registration Statement, it will not
contain any untrue statement of a material fact or omit to state any material
fact required to be stated therein or necessary to make the statements therein
not misleading and that, in the case of the Prospectus, such Prospectus will not
contain any untrue statement of a material fact or omit to state any material
fact required to be stated therein or necessary to make the statements therein,
in the light of the circumstances under which they were made, not misleading,
except if the existence of such fact or the happening of any such event results
from a corporate development that is being pursued by the Company (A) the
disclosure of which in the Company's reasonable judgment would have a material
adverse effect on the Company and its subsidiaries taken as a whole and (B)
which, in the Company's reasonable judgment after consultation with counsel
would not, in the absence of an effective Registration Statement, be required to
be disclosed by the Company;

    (d) Use all reasonable efforts to avoid the issuance of, or, if issued,
obtain the withdrawal of any order enjoining or suspending the use or
effectiveness of a Registration

                                       9
<PAGE>

Statement or the lifting of any suspension of the qualification (or exemption
from qualification) of any of the Transfer Restricted Securities for sale in any
jurisdiction, at the earliest practicable moment;

    (e) Subject to Section 2(c) hereof, if reasonably requested by the managing
underwriters, if any, or the Holders of a majority in aggregate principal
amount, in the case of the Debentures, or the number, in the case of the Common
Stock, of the Transfer Restricted Securities being sold in connection with such
offering, (i) promptly incorporate in a Prospectus supplement or post-effective
amendment such information as the managing underwriters, if any, and such
Holders agree should be included therein, and (ii) make all required filings of
such Prospectus supplement or such post-effective amendment as soon as
practicable after the Company has received notification of the matters to be
incorporated in such Prospectus supplement or post-effective amendment;
provided, however, that the Company shall not be required to take any action
--------  -------
pursuant to this Section 4(e) that would, in the opinion of counsel for the
Company, violate applicable law;

    (f) Furnish to each Holder who so requests, Special Counsel and each
managing underwriter, if any, without charge, at least one conformed copy of
each Registration Statement and each amendment thereto, including financial
statements (but excluding schedules, all documents incorporated or deemed to be
incorporated therein by reference and all exhibits, unless requested in writing
by such Holder, counsel or managing underwriter);

    (g) Deliver to each Holder, Special Counsel and the underwriters, if any,
without charge, as many copies of the Prospectus or Prospectuses (including each
form of prospectus) and each amendment or supplement thereto to such persons who
reasonably request; and, unless the Company shall have given notice to such
Holder pursuant to Section 4(c)(vi), the Company hereby consents to the use of
such Prospectus and each amendment or supplement thereto by each of the selling
Holders of Transfer Restricted Securities and the underwriters, if any, in
connection with the offering and sale of the Transfer Restricted Securities
covered by such Prospectus and any amendment or supplement thereto;

    (h) Prior to any public offering of Transfer Restricted Securities, use all
reasonable efforts to register or qualify, or cooperate with the Holders of
Transfer Restricted Securities to be sold, the underwriters, if any, and their
respective counsel in connection with the registration or qualification (or
exemption from such registration or qualification) of, such Transfer Restricted
Securities for offer and sale under the securities or Blue Sky laws of such
jurisdictions within the United States as any Holder or

                                       10
<PAGE>

underwriter reasonably requests in writing, keep each such registration or
qualification (or exemption therefrom) effective during the period such
Registration Statement is required to be kept effective and do any and all other
acts or things necessary legally to enable the disposition in such jurisdictions
of the Transfer Restricted Securities covered by the applicable Registration
Statement; provided, however, that the Company shall not be required to
           --------  -------
qualify generally to do business in any jurisdiction where it is not then so
qualified or take any action that would subject it to general service of process
in any such jurisdiction where it is not then so subject;

    (i) In connection with any sale or transfer of Transfer Restricted
Securities that will result in such securities no longer being Transfer
Restricted Securities, and unless any Transfer Restricted Securities shall be in
only book-entry form, cooperate with the Holders and the managing underwriters,
if any, to (A) facilitate the timely preparation and delivery of certificates
representing Transfer Restricted Securities to be sold, which certificates shall
not bear any restrictive legends, shall bear a CUSIP number different from the
CUSIP number for the Transfer Restricted Securities and shall be in a form
eligible for deposit with The Depository Trust Company and (B) enable such
Transfer Restricted Securities to be in such denominations and registered in
such names as the managing underwriters, if any, or Holders may request at least
two Business Days prior to any sale of Transfer Restricted Securities;

    (j) Upon the occurrence of any event contemplated by Section 4(c)(vi)
hereof, as promptly as practicable, prepare a supplement or amendment,
including, if appropriate, a post-effective amendment, to each Registration
Statement or a supplement to the related Prospectus or any document incorporated
or deemed to be incorporated therein by reference, and file any other required
document so that, as thereafter delivered, such Prospectus will not contain an
untrue statement of a material fact or omit to state a material fact required to
be stated therein or necessary to make the statements therein, in the light of
the circumstances under which they were made, not misleading;

    (k) Prior to the effective date of the Registration Statement relating to
the Transfer Restricted Securities, to provide a CUSIP number for the Transfer
Restricted Securities to be sold pursuant to the Registration Statement;

    (l) Enter into such agreements (including an underwriting agreement in form,
scope and substance as is customary in underwritten offerings) reasonably
satisfactory to the Company and take all such other reasonable actions in
connection therewith (including those reasonably requested by the managing
underwriters, if any, or the Holders of a majority in aggregate principal
amount, in the case of the Debentures, or the number, in the case of the Common
Stock, of the Transfer Restricted Securities being

                                       11
<PAGE>

sold) in order to expedite or facilitate the disposition of such Transfer
Restricted Securities, and in such connection, whether or not an underwriting
agreement is entered into and whether or not the registration is an underwritten
registration, (i) make such representations and warranties to the Holders of
such Transfer Restricted Securities and the underwriters, if any, with respect
to the business of the Company and its subsidiaries (including with respect to
businesses or assets acquired or to be acquired by any of them), and the
Registration Statement, Prospectus and documents, if any, incorporated or deemed
to be incorporated by reference therein, in each case, in form, substance and
scope as are customarily made by issuers to underwriters in underwritten
offerings and reasonably acceptable to the Company, and confirm the same if and
when requested; (ii) seek to obtain opinions of counsel to the Company and
updates thereof, which counsel and opinions (in form, scope and substance) shall
be reasonably satisfactory to the managing underwriters, if any, and Special
Counsel to the Holders of the Transfer Restricted Securities being sold,
addressed to each of the underwriters, if any, covering the matters customarily
covered in opinions requested in underwritten offerings (including any such
matters as may be reasonably requested by such Special Counsel and
underwriters); (iii) use all reasonable efforts to obtain customary "cold
comfort" letters and updates thereof from the independent certified public
accountants of the Company (and, if necessary, any other independent certified
public accountants of any subsidiary of the Company or of any business acquired
or to be acquired by the Company for which financial statements and financial
data is, or is required to be, included in the Registration Statement),
addressed (where reasonably possible) to each selling Holder of Transfer
Restricted Securities and each of the underwriters, if any, such letters to be
in customary form and covering matters of the type customarily covered in "cold
comfort" letters in connection with underwritten offerings; (iv) if an
underwriting agreement is entered into, the same shall contain indemnification
provisions and procedures no less favorable to the selling Holders of Transfer
Restricted Securities and the underwriters, if any, than those set forth in
Section 6 hereof (or such other provisions and procedures acceptable to the
Company and Holders of a majority in aggregate principal amount of the Transfer
Restricted Securities covered by such Registration Statement and the managing
underwriters); and (v) deliver such documents and certificates as may be
reasonably requested by the Holders of a majority in aggregate principal amount,
in the case of the Debentures, or the number, in the case of the Common Stock,
of the Transfer Restricted Securities being sold in connection with this
offering, Special Counsel or the managing underwriters, if any, to evidence the
continued validity of the representations and warranties made pursuant to clause
(i) of this Section 4(l) and to evidence compliance with any customary
conditions contained in the underwriting agreement or other agreement entered
into by the Company;

                                       12
<PAGE>

    (m) Make available for inspection by a representative of the Holders of
Transfer Restricted Securities being sold, any underwriter participating in any
such disposition of Transfer Restricted Securities, if any, and any attorney,
consultant or accountant retained by such selling Holders or underwriter, at the
offices where normally kept, during reasonable business hours, all financial and
other records, pertinent corporate documents and properties of the Company and
its subsidiaries as they may reasonably request (including with respect to
business and assets acquired or to be acquired to the extent that such
information is available to the Company), and cause the officers, directors,
agents and employees of the Company and its subsidiaries (including with respect
to business assets acquired or to be acquired to the extent that such
information is available to the Company) to supply all information in each case
reasonably requested by any such representative, underwriter, attorney,
consultant or accountant in connection with such Registration Statement;
provided, however, that any information that is reasonably and in good faith
--------  -------
designated by the Company in writing as confidential at the time of delivery of
such information shall be kept confidential by such persons (and such persons
shall so agree in writing), unless (i) disclosure of such information is
required by court or administrative order or is necessary to respond to
inquiries of regulatory authorities, (ii) disclosure of such information is
required by law (including any disclosure requirements pursuant to Federal
securities laws in connection with the filing of any Registration Statement or
the use of any prospectus referred to in this Agreement), (iii) such information
becomes generally available to the public other than as a result of a disclosure
or failure to safeguard by any such person or (iv) such information becomes
available to any such person from a source other than the Company and such
source is not bound by a confidentiality agreement;

    (n) Cause the Indenture to be qualified under the TIA not later than the
effective date of the Registration Statement relating to the Transfer Restricted
Securities; and in connection therewith, cooperate with the Trustee under the
Indenture and the Holders of the Transfer Restricted Securities to effect such
changes to the Indenture, if any, as may be required for such Indenture to be so
qualified in accordance with the terms of the TIA; and execute, and use all
reasonable efforts to cause the Trustee to execute, all customary documents as
may be required to effect such changes, and all other forms and documents
(including the Form T-1) required to be filed with the SEC to enable the
Indenture to be so qualified under the TIA in a timely manner;

    (o) Comply with applicable rules and regulations of the SEC and make
generally available to its security holders earning statements satisfying the
provisions of Section 11(a) of the Securities Act and Rule 158 thereunder (or
any similar rule promulgated under the Securities Act), no later than 45 days
after the end of any 12-month period (or 90 days after the end of any 12-month
period if such period is a fiscal

                                       13
<PAGE>

year), commencing on the first day of the first fiscal quarter after the
effective date of a Registration Statement, which statement shall cover said
period, consistent with the requirements of Rule 158; and

    (p) (i)  list all Common Stock covered by such Registration Statement on any
securities exchange on which the Common Stock is then listed or (ii) authorize
for quotation on The Nasdaq Stock Market all Common Stock covered by such
Registration Statement if the Common Stock is then so authorized for quotation.

    5.  Registration Expenses.
        ---------------------

    (a) All fees and expenses incident to the performance of or compliance with
this Agreement by the Company shall be borne by it whether or not any
Registration Statement is filed or becomes effective and whether or not any
securities are issued or sold pursuant to any Registration Statement.  The fees
and expenses referred to in the foregoing sentence shall include, without
limitation, (i) all registration and filings fees (including without limitation,
fees and expenses with respect to filings required to be made with the National
Association of Securities Dealers, Inc.), (ii) printing expenses (including,
without limitation, expenses of printing certificates for Transfer Restricted
Securities in a form eligible for deposit with The Depository Trust Company and
of printing Prospectuses if the printing of Prospectuses is required by the
managing underwriters, if any, or by the Holders of a majority in aggregate
principal amount of the Transfer Restricted Securities included in any
Registration Statement, (iii) messenger, telephone and delivery expenses, (iv)
fees and disbursements of counsel for the Company and Special Counsel for the
Holders (plus any local counsel, deemed appropriate by the Holders of a majority
in aggregate principal amount of the Transfer Restricted Securities) in
accordance with the provisions of Section 5(b) hereof, (v) fees and
disbursements of all independent certified public accountants referred to in
Section 4(l)(iii) (including, without limitation, the expenses of any special
audit and "cold comfort" letters required by or incident to such performance),
(vi) Securities Act liability insurance, if the Company so desires such
insurance, and (vii) fees and expenses of all other persons retained by the
Company.  In addition, the Company shall pay its internal expenses (including,
without limitation, all salaries and expenses of its officers and employees
performing legal or accounting duties), the expense of an annual audit, and the
fees and expenses incurred in connection with the listing of the securities to
be registered on any securities exchange.  Notwithstanding the foregoing or
anything in this Agreement to the contrary, each Holder shall pay all
underwriting discounts and commissions of any underwriters with respect to any
Transfer Restricted Securities sold by it.

                                       14
<PAGE>

    (b) In connection with any registration hereunder, the Company shall
reimburse the Holders of the Transfer Restricted Securities being registered or
tendered for in such registration for the fees and disbursements of not more
than one firm of attorneys representing the selling Holders (in addition to any
local counsel), in an amount not to exceed $25,000 in the aggregate for all such
registrations, which firm shall be chosen by the Holders of a majority in
aggregate principal amount, in the case of the Debentures, or the number, in the
case of the Common Stock, of the Transfer Restricted Securities.  Chadbourne &
Parke LLP shall be Special Counsel for all purposes hereof unless and until
another Special Counsel shall have been selected by a majority in aggregate
principal amount of the Transfer Restricted Securities and notice hereof shall
have been given to the Company.

                                       15
<PAGE>

    6.  Indemnification.
        ---------------

    (a) The Company agrees to indemnify and hold harmless (i) the Initial
Purchasers, (ii) each Holder of Transfer Restricted Securities, (iii) each
person, if any, who controls (within the meaning of Section 15 of the Securities
Act or Section 20 of the Exchange Act) any of the foregoing (any of the persons
referred to in this clause (iii) being hereinafter referred to as a "controlling
person"), and (iv) the respective officers, directors, partners, employees,
representatives and agents of the Initial Purchasers, each Holder of Transfer
Restricted Securities, or any controlling person (any person referred to in
clause (i), (ii), (iii) or (iv) may hereinafter be referred to as an
"Indemnified Person"), from and against any and all losses, claims, damages,
liabilities, expenses and judgments caused by any untrue statement or alleged
untrue statement of a material fact contained in any Registration Statement,
Prospectus or form of Prospectus or in any amendment or supplement thereto or in
any preliminary Prospectus, or caused by any omission or alleged omission to
state therein a material fact required to be stated therein or necessary to make
the statements therein (in the case of any Prospectus or form of Prospectus or
supplement thereto, in the light of the circumstances under which they were
made) not misleading, except insofar as such losses, claims, damages,
liabilities, expenses or judgments are caused by any such untrue statement or
omission or alleged untrue statement or omission based upon information relating
to any Indemnified Person furnished in writing to the Company by or on behalf of
such Indemnified Person expressly for use therein; provided that the foregoing
                                                   --------
indemnity with respect to any preliminary Prospectus shall not inure to the
benefit of any Indemnified Person from whom the person asserting such losses,
claims, damages, liabilities, expenses and judgments purchased securities if
such untrue statement or omission or alleged untrue statement or omission made
in such preliminary Prospectus is eliminated or remedied in the Prospectus and a
copy of the Prospectus shall not have been furnished to such person in a timely
manner, unless such Prospectus was not furnished because the Company failed to
provide the Indemnified Person with sufficient copies of such corrected
Prospectus within the time period required.

    (b) In case any action shall be brought against any Indemnified Person,
based upon any Registration Statement or any such Prospectus or any amendment or
supplement thereto and with respect to which indemnity may be sought against the
Company, such Indemnified Person shall promptly notify the Company in writing
and the Company shall assume the defense thereof, including the employment of
counsel reasonably satisfactory to such Indemnified Person and payment of all
fees and expenses.  Any Indemnified Person shall have the right to employ
separate counsel in any such action and participate in (but not control) the
defense thereof, but the fees and expenses of such counsel shall be at the
expense of such Indemnified Person, unless (i) the

                                       16
<PAGE>

employment of such counsel shall have been specifically authorized in writing by
the Company, (ii) the Company shall have failed to assume the defense and employ
counsel or (iii) such Indemnified Person or Persons shall have been advised by
counsel that there may be a conflict between the positions of the indemnifying
party or parties and of the indemnified party or parties in conducting the
defense of such action or that there may be legal defenses available to such
Indemnified Person or Persons different from or in addition to those available
to the indemnifying party or parties (in which case the Company shall not have
the right to assume the defense of such action on behalf of such Indemnified
Person, it being understood, however, that the Company shall not, in connection
with any one such action or separate but substantially similar or related
actions in the same jurisdiction arising out of the same general allegations or
circumstances, be liable for the fees and expenses of more than one separate
firm of attorneys, (in addition to any local counsel) for all such Indemnified
Persons, which firm shall be designated in writing by such Indemnified Persons
and shall be reasonably satisfactory to the Company, and that all such fees and
expenses shall be reimbursed as they are incurred). The Company shall not be
liable for any settlement of any such action effected without its written
consent but if settled with the written consent of the Company, the Company
agrees to indemnify and hold harmless any Indemnified Person from and against
any loss or liability by reason of such settlement. No indemnifying party shall,
without the prior written consent of the indemnified party (which consent shall
not be unreasonably withheld), effect any settlement of any pending or
threatened action in respect of which any indemnified party is or could have
been a party and indemnity could have been sought hereunder by such indemnified
party, unless such settlement includes an unconditional release of such
indemnified party from all liability on claims that are the subject matter of
such action.

    (c) In connection with any Registration Statement in which the Holder of
Transfer Restricted Securities is participating, such Holder of Transfer
Restricted Securities agrees, severally and not jointly, to indemnify and hold
harmless the Company, its directors, its officers and any person controlling the
Company within the meaning of Section 15 of the Securities Act or Section 20 of
the Exchange Act, to the same extent as the foregoing indemnity from the Company
to each Indemnified Person but only with reference to information relating to
such Indemnified Person furnished in writing by or on behalf of such Indemnified
Person expressly for use in such Registration Statement.  In case any action
shall be brought against the Company, any of its directors, any such officer or
any person controlling the Company based on such Registration Statement and in
respect of which indemnity may be sought against any Indemnified Person, the
Indemnified Person shall have the rights and duties given to the Company (except
that if the Company shall have assumed the defense thereof, such Indemnified
Person shall not be required to do so, but may employ separate counsel therein
and participate in (but not

                                       17
<PAGE>

control) the defense thereof but the fees and expenses of such counsel shall be
at the expense of such Indemnified Person), and the Company, its directors, any
such officers and any person controlling the Company shall have the rights and
duties given to the Indemnified Person, by Section 6(b) hereof.

    (d) If the indemnification provided for in this Section 6 is unavailable to
an indemnified party in respect of any losses, claims, damages, liabilities,
expenses or judgments referred to therein, then each indemnifying party, in lieu
of indemnifying such indemnified party, shall contribute to the amount paid or
payable by such indemnified party as a result of such losses, claims, damages,
liabilities, expenses and judgments (i) in such proportion as is appropriate to
reflect the relative benefits received by the Company on the one hand and each
Indemnified Person on the other hand from the offering of the Transfer
Restricted Securities or (ii) if the allocation provided by clause (i) above is
not permitted by applicable law, in such proportion as is appropriate to reflect
not only the relative benefits referred to in clause (i) above but also the
relative fault of the Company and each such Indemnified Person in connection
with the statements or omissions which resulted in such losses, claims, damages,
liabilities, expenses or judgments, as well as any other relevant equitable
considerations.  The relative fault of the Company and each such Indemnified
Person shall be determined by reference to, among other things, whether the
untrue or alleged untrue statement of a material fact or the omission to state a
material fact relates to information supplied by the Company or such Indemnified
Person and the parties' relative intent, knowledge, access to information and
opportunity to correct or prevent such statement or omission.

    The Company and the Initial Purchasers agree that it would not be just and
equitable if contribution pursuant to this Section 6(d) were determined by pro
rata allocation (even if the Indemnified Persons were treated as one entity for
such purpose) or by any other method of allocation which does not take account
of the equitable considerations referred to in the immediately preceding
paragraph.  The amount paid or payable by an indemnified party as a result of
the losses, claims, damages, liabilities, expenses or judgments referred to in
the immediately preceding paragraph shall be deemed to include, subject to the
limitations set forth above, any legal or other expenses reasonably incurred by
such indemnified party in connection with investigating or defending any such
action or claim.  Notwithstanding the provisions of this Section 6, no
Indemnified Person shall be required to contribute any amount in excess of the
amount by which the total proceeds received by it in connection with the sale of
the Transfer Restricted Securities pursuant to this Agreement exceeds the amount
of any damages which such Indemnified Person has otherwise been required to pay
by reason of such untrue or alleged untrue statement or omission or alleged
omission.  No person guilty of fraudulent misrepresentation (within the meaning
of Section 11(f) of the Securities Act)

                                       18
<PAGE>

shall be entitled to contribution from any person who was not guilty of such
fraudulent misrepresentation. The Indemnified Persons' obligations to contribute
pursuant to this Section 6(d) are several in proportion to the respective amount
of Transfer Restricted Securities included in and sold pursuant to any such
Registration Statement by each Indemnified Person and not joint.

    (e) The agreements contained in this Section 6 shall survive the sale of the
Transfer Restated Securities pursuant to any Registration Statement and shall
remain in full force and effect, regardless of any investigation made by or on
behalf of any Indemnified Person.

    7.  Rules 144 and 144A.
        ------------------

    The Company shall use all reasonable efforts to file the reports required to
be filed by it under the Securities Act and the Exchange Act in a timely manner
and, if at any time it is not required to file such reports but in the past had
been required to or did file such reports, it will, upon the request of any
Holder, make available other information as required by, and so long as
necessary to permit sales of, its Transfer Restricted Securities pursuant to
Rule 144 and Rule 144A.  Notwithstanding the foregoing, nothing in this Section
7 shall be deemed to require the Company to register any of its securities
pursuant to the Exchange Act.

    8.  Underwritten Registrations.
        --------------------------

    If any of the Transfer Restricted Securities covered by the Shelf
Registration Statement are to be sold in an underwritten offering, the
investment banker or investment bankers and manager or managers that will
administer the offering will be investment bankers of recognized national
standing selected by the Holders of a majority in aggregate principal amount, in
the case of the Debentures, or the number, in the case of the Common Stock, of
such Transfer Restricted Securities included in such offering, subject to the
consent of the Company (which will not be unreasonably withheld or delayed).

    No person may participate in any underwritten registration hereunder unless
such person (i) agrees to sell such person's Transfer Restricted Securities on
the basis reasonably provided in any underwriting arrangements approved by the
persons entitled hereunder to approve such arrangements 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.

    9.  Miscellaneous.
        -------------

                                       19
<PAGE>

    (a) Remedies.  In the event of a breach by the Company, or by a Holder of
        --------
Transfer Restricted Securities, of any of their obligations under this
Agreement, each Holder of Transfer Restricted Securities or the Company,
respectively, in addition to being entitled to exercise all rights granted by
law, including recovery of damages, will be entitled to specific performance of
its rights under this Agreement.  The Company and each Holder of Transfer
Restricted Securities agree that monetary damages would not be adequate
compensation for any loss incurred by reason of a breach by it of any of the
provisions of this Agreement and hereby further agree that, in the event of any
action for specific performance in respect of such breach, they shall waive the
defense that a remedy at law would be adequate.

    (b) No Inconsistent Agreements.  The Company shall not enter into any
        --------------------------
agreement with respect to its securities that is inconsistent with the rights
granted to the holders of Transfer Restricted Securities in this Agreement or
otherwise conflicts with the provisions hereof.  The Company is not currently a
party to any agreement granting any registration rights with respect to any of
its securities to any person which conflicts with the Company's obligations
hereunder or gives any other party the right to include any securities in any
Registration Statement filed pursuant hereto, except for such rights and
conflicts as have been irrevocably waived.  Without limiting the generality of
the foregoing, without the written consent of the Holders of a majority in
aggregate principal amount in the case of the Debentures, or the number, in the
case of Common Stock, of the Transfer Restricted Securities, the Company shall
not grant to any person the right to request it to register any of its
securities under the Securities Act unless the rights so granted are subject in
all respect to the prior rights of the holders of Transfer Restricted Securities
set forth herein, and are not otherwise in conflict or inconsistent with the
provisions of this Agreement.

    (c) No Adverse Action Affecting the Transfer Restricted Securities.  Subject
        --------------------------------------------------------------
to the Company's right to suspend use of the Prospectus pursuant to Section 2(d)
hereof, or give a notice pursuant to Section 4(c)(vi) hereof, the Company will
not take any action with respect to the Transfer Restricted Securities which
would adversely affect the ability of any of the Holders of Transfer Restricted
Securities to include such Transfer Restricted Securities in a registration
undertaken pursuant to this Agreement.

    (d) No Piggyback on Registrations.  The Company shall not grant to any of
        -----------------------------
its security holders (other than the Holders of Transfer Restricted Securities
in such capacity) the right to include any of its securities in any Shelf
Registration Statement other than Transfer Restricted Securities.

                                       20
<PAGE>

    (e) Amendments and Waivers.  The provisions of this Agreement, including the
        ----------------------
provisions of this sentence, may not be amended, modified or supplemented, and
waivers or consents to departures from the provisions hereof may not be given,
without the written consent of the Holders of a majority in aggregate principal
amount, in the case of the Debentures, or the number, in the case of the Common
Stock, of the Transfer Restricted Securities.  Notwithstanding the foregoing, a
waiver or consent to depart from the provisions hereof with respect to a matter
that relates exclusively to the rights of Holders of Transfer Restricted
Securities whose securities are being sold pursuant to a Registration Statement
and that does not directly or indirectly affect the rights of other Holders of
Transfer Restricted Securities may be given by Holders of a majority in
aggregate principal amount, in the case of the Debentures, or the number, in the
case of the Common Stock, of the Transfer Restricted Securities being sold by
such Holders pursuant to such Registration Statement; provided, however, that
                                                      --------  -------
the provisions of this sentence may not be amended, modified, or supplemented
except in accordance with the provisions of the immediately preceding sentence.

    (f) Notices.  All notices and other communications provided for herein shall
        -------
be made in writing by hand-delivery, next-day air courier, certified first-class
mail, return receipt requested or telecopy:

               (i)   if to a Holder of Transfer Restricted Securities, to the
address of such Holder as it appears in the Debenture or Common Stock register
of the Company, as applicable; and

               (ii)  if to the Company, to:

                     VerticalNet, Inc.
                     700 Dresher Road
                     Suite 100
                     Horsham, PA  19044
                     Telecopy: (215) 784-1968
                     Attention:

                     with a copy to:

                     Morgan, Lewis & Bockius LLP
                     1701 Market Street
                     Philadelphia, PA  19103-6993
                     Telecopy:  (215) 963-5299
                     Attention:  James McKenzie, Esq.

                                       21
<PAGE>

             (iii)  if to the Special Counsel, to:

                    Chadbourne & Parke LLP
                    30 Rockefeller Plaza
                    New York, NY  10112
                    Telecopy:  (212) 541-5369
                    Attention:  Barbara L. Becker, Esq.

or such other Special Counsel at such other address and telecopy number as a
majority in aggregate principal amount of the Transfer Restricted Securities
shall have given notice to the Company as contemplated by Section 5(b) hereof.

    Except as otherwise provided in this Agreement, all such communications
shall be deemed to have been duly given, when delivered by hand, if personally
delivered; one Business Day after being timely delivered to a next-day air
courier, five Business Days after being deposited in the mail, postage prepaid,
if mailed; and when receipt is acknowledged by the recipient's telecopier
machine, if telecopied.

    (g) Successors and Assigns.  This Agreement shall inure to the benefit of
        ----------------------
and be binding upon the successors and permitted assigns of each of the parties
and shall inure to the benefit of each existing and future Holder of Transfer
Restricted Securities.  The Company may not assign its rights or obligations
hereunder without the prior written consent of each Holder of Transfer
Restricted Securities, other than by operation of law pursuant to a merger or
consolidation to which the Company is a party.  In the event the Debentures
become convertible into common stock of another person pursuant to Section 12.11
of the Indenture, the Company shall cause such person to assume the Company's
obligations hereunder.

    (h) Counterparts.  This Agreement may be executed in any number of
        ------------
counterparts and by the parties hereto in separate counterparts each of which
when so executed shall be deemed to be an original and all of which taken
together shall constitute one and the same Agreement.

          (i) Governing Law; Submission to Jurisdiction.
              -----------------------------------------

    THIS AGREEMENT SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE
LAWS OF THE STATE OF NEW YORK, AS APPLIED TO CONTRACTS MADE AND PERFORMED WITHIN
THE STATE OF NEW YORK WITHOUT REGARD TO PRINCIPLES OF CONFLICTS OF LAW.  THE
COMPANY HEREBY IRREVOCABLY SUBMITS TO THE JURISDICTION OF ANY NEW YORK STATE
COURT SITTING IN THE BOROUGH OF MANHATTAN IN THE

                                       22
<PAGE>

CITY OF NEW YORK OR ANY FEDERAL COURT SITTING IN THE BOROUGH OF MANHATTAN IN
THE CITY OF NEW YORK IN RESPECT OF ANY SUIT, ACTION OR PROCEEDING ARISING OUT OF
OR RELATING TO THIS AGREEMENT, AND IRREVOCABLY ACCEPTS FOR ITSELF AND IN RESPECT
OF ITS PROPERTY, GENERALLY AND UNCONDITIONALLY, JURISDICTION OF THE AFORESAID
COURTS. THE COMPANY IRREVOCABLY WAIVES, TO THE FULLEST EXTENT IT MAY EFFECTIVELY
DO SO UNDER APPLICABLE LAW, ANY OBJECTION THAT IT MAY NOW OR HEREAFTER HAVE TO
THE LAYING OF THE VENUE OF ANY SUCH SUIT, ACTION OR PROCEEDING BROUGHT IN ANY
SUCH COURT AND ANY CLAIM THAT ANY SUCH SUIT, ACTION OR PROCEEDING BROUGHT IN ANY
SUCH COURT HAS BEEN BROUGHT IN AN INCONVENIENT FORUM.

    (j) Severability.  The remedies provided herein are cumulative and not
        ------------
exclusive of any remedies provided by law.  If any term, provision, covenant or
restriction of this Agreement is held by a court of competent jurisdiction to be
invalid, illegal, void or unenforceable, the remainder of the terms, provisions,
covenants and restrictions set forth herein shall remain in full force and
effect and shall in no way be affected, impaired or invalidated, and the parties
hereto shall use their best efforts to find and employ an alternative means to
achieve the same or substantially the same result as that contemplated by such
term, provision, covenant or restriction.  It is hereby stipulated and declared
to be the intention of the parties that they would have executed the remaining
terms, provisions, covenants and restrictions without including any of such that
may be hereafter declared invalid, illegal, void or unenforceable.

    (k) Headings.  The headings in this Agreement are for convenience of
        --------
reference only and shall not limit or otherwise affect the meaning hereof.  All
references made in this Agreement to "Section" and "paragraph" refer to such
Section or paragraph of this Agreement, unless expressly stated otherwise.

    (l) Attorneys' Fees.  In any action or proceeding brought to enforce any
        ---------------
provision of this Agreement, or where any provision hereof is validly asserted
as a defense, the prevailing party, as determined by the court, shall be
entitled to recover its reasonable attorneys' fees in addition to any other
available remedy.

                                       23
<PAGE>

    IN WITNESS WHEREOF, the parties have caused this Registration Rights
Agreement to be duly executed as of the date first written above.

                         VERTICALNET, INC.

                         By:_____________________________
                            Name:
                            Title:


                         LEHMAN BROTHERS INC.
                         HAMBRECHT & QUIST LLC
                         SG COWEN SECURITIES CORPORATION
                         VOLPE BROWN WHELAN & COMPANY, LLC

                         BY  LEHMAN BROTHERS INC.


                         By:______________________________
                            Name:
                            Title:

                                       24