<PAGE>

                                                                     EXHIBIT 4.2

   =========================================================================

                             CARSDIRECT.COM, INC.

                          FOURTH AMENDED AND RESTATED

                           INVESTOR RIGHTS AGREEMENT

                               October 27, 1999
   =========================================================================
<PAGE>

                               TABLE OF CONTENTS


<TABLE>
<CAPTION>
                                                                                                                       Page
                                                                                                                       ----
<S>                                                                                                                    <C>
1.       Certain Definitions.........................................................................................     2
2.       Restrictions on Transferability.............................................................................     3
3.       Restrictive Legend..........................................................................................     3
4.       Notice of Proposed Transfers................................................................................     4
5.       Registration................................................................................................     5
         5.1      Requested Registration.............................................................................     5
         5.2      Company Registration...............................................................................     7
         5.3      Registration on Form S-3...........................................................................     8
         5.4      Subsequent Registration Rights.....................................................................     9
         5.5      Expenses of Registration...........................................................................    10
         5.6      Registration Procedures............................................................................    10
         5.7      Indemnification....................................................................................    10
         5.8      Information by Holder..............................................................................    12
         5.9      Rule 144 Reporting.................................................................................    12
         5.10     Termination of Registration Rights.................................................................    13
6.       Financial Information Rights................................................................................    13
7.       Lockup Agreement............................................................................................    14
8.       Right of First Refusal......................................................................................    15
9.       Vesting of Employee Options.................................................................................    17
10.      Employment, Confidential Information and Invention Assignment Agreements....................................    17
11.      Transfer of Rights..........................................................................................    18
12.      Series B Preferred Board Members............................................................................    18
13.      Amendment...................................................................................................    18
14.      Governing Law...............................................................................................    18
15.      Entire Agreement............................................................................................    18
16.      Notices, etc................................................................................................    19
17.      Counterparts................................................................................................    19
</TABLE>

                                                                             -i-
<PAGE>

                               TABLE OF CONTENTS
                                  (Continued)

EXHIBITS
--------

      A.        Schedule of Purchasers

                                                                            -ii-
<PAGE>

                             CARSDIRECT.COM, INC.

                          FOURTH AMENDED AND RESTATED

                           INVESTOR RIGHTS AGREEMENT

     This Fourth Amended and Restated Investor Rights Agreement (this
"Agreement") is made effective as of October 27, 1999, by and among
CarsDirect.com, Inc., a Delaware corporation (the "Company"), purchasers of the
Company's Series D Preferred Stock who are signatories to this Agreement (the
"Purchasers"), the Series A Investors (as defined herein), the Series B
Investors (as defined herein) and the Series C Investors (as defined herein) and
other persons or entities who are or become signatories to this Agreement and/or
the Prior Agreement (as defined below).

                                   RECITALS

     A.   In connection with the sale and issuance of its Series C Preferred
Stock, the Company entered into that certain Third Amended and Restated Investor
Rights Agreement dated May 7, 1999 (the "Prior Agreement") with the purchasers
of Series A Preferred Stock (the "Series A Investors"), the purchasers of Series
B Preferred Stock (the "Series B Investors") and the purchasers of the Series C
Preferred Stock (the "Series C Investors").

     B.   The Company and the Purchasers are parties to the Series D Preferred
Stock Purchase Agreement dated as of October 27, 1999, as may be amended from
time to time (the "Purchase Agreement"), whereby the Company will sell, and the
Purchasers will buy, Series D Preferred Stock of the Company.

     C.   The obligations of the Company and the Purchasers under the Purchase
Agreement are conditioned, among other things, upon the execution and delivery
of this Agreement by the Company and the Purchasers.

     D.   Section 12 of the Prior Agreement provides that the consent of the
Company and a majority of the outstanding Registrable Securities is required to
amend the Prior Agreement.

     E.   The Company and certain stockholders, who together hold not less than
a majority of the Registrable Securities (as defined under the Prior Agreement)
now desire to amend and restate the Prior Agreement in its entirety as set forth
below in order to add additional Purchasers as parties hereto and to make
certain other changes.
<PAGE>

                                   AGREEMENT

     NOW, THEREFORE, in consideration of the mutual promises and covenants
herein, the receipt and sufficiency are hereby acknowledged, the parties hereto
agree to amend and restate the Prior Agreement in its entirety as follows:

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

          "Commission" means the Securities and Exchange Commission or any other
federal agency at the time administering the Securities Act.

          "Conversion Stock" means the Company's Common Stock issued or issuable
pursuant to conversion of the Preferred Stock.

          "Exchange Act" means the Securities Exchange Act of 1934, as amended,
or any similar federal rule or statute and the rules and regulations of the
Commission thereunder, all as the same shall be in effect at the time.

          "Holder" means (i) any Series A Investor, any Series B or Series C
Investor or Purchaser holding Registrable Securities, (ii) any person or entity
that the Board of Directors of the Company authorizes to be a Holder and who
becomes a signatory to this Agreement, and (iii) any person holding Registrable
Securities to whom the rights under this Agreement have been transferred in
accordance with Section 11 hereof or, prior to the date hereof, in accordance
with Section 11 of the Prior Agreement.

          "Initiating Holders" means any Holder or Holders who, in the
aggregate, hold not less than 50% of the Registrable Securities then
outstanding.

          "Preferred Stock" shall mean the Company's Series A Preferred Stock,
Series B Preferred Stock, Series C Preferred Stock, and Series D Preferred
Stock.

          "Qualified Initial Public Offering" shall mean the Company's initial
public offering pursuant to an effective registration statement under the
Securities Act covering the offer and sale of the Company's Common Stock to the
public with gross proceeds to the Company not less than $20 million at a per
share price of at least $7.00.

          "Registrable Securities" means (i) the Conversion Stock, (ii) any
Common Stock of the Company issued or issuable in respect of any of the
foregoing upon any stock split, stock dividend, recapitalization or similar
event; provided, however, that securities shall only be treated as Registrable
Securities if and so long as (x) they have not been registered or sold to or
through a broker or dealer or underwriter in a public distribution or a public
securities transaction and (y) the

                                                                             -2-
<PAGE>

registration rights with respect to such securities have not terminated pursuant
to Section 5.10, and (iii) Common Stock of the Company that the Board of
Directors of the Company authorizes to be Registrable Securities under this
Agreement.

          The terms "register," "registered" and "registration" refer to a
registration effected by preparing and filing a registration statement in
compliance with the Securities Act, and the declaration or ordering of the
effectiveness of such registration statement.

          "Registration Expenses" shall mean all expenses, except as otherwise
stated below, incurred by the Company in complying with Sections 5.1, 5.2 and
5.3 hereof, including without limitation, all registration, qualification and
filing fees, printing expenses, escrow fees, fees and disbursements of counsel
for the Company, blue sky fees and expenses, the expense of any special audits
incident to or required by any such registration (but excluding the compensation
of regular employees of the Company which shall be paid in any event by the
Company). Registration Expenses shall also include the fees and disbursements
for one special counsel to the selling stockholders, not to exceed $15,000 per
registration.

          "Restricted Securities" shall mean the securities of the Company
required to bear the legends set forth in Section 3 hereof.

          "Rule 144" and "Rule 145" shall mean Rules 144 and 145, respectively,
promulgated under the Securities Act, or any similar federal rules thereunder,
all as the same shall be in effect at the time.

          "Securities Act" shall mean the Securities Act of 1933, as amended, or
any similar federal rule or statute and the rules and regulations of the
Commission thereunder, all as the same shall be in effect at the time.

          "Selling Expenses" shall mean all underwriting discounts, selling
commissions and stock transfer taxes applicable to the securities registered by
the Holders and, except as set forth above, all fees and disbursements of
counsel for any Holder.

     2.   Restrictions on Transferability. The Preferred Stock, the Conversion
          -------------------------------
Stock and any other securities issued in respect of such stock upon any stock
split, stock dividend, recapitalization, merger, or similar event, shall not be
sold, assigned, transferred or pledged except upon the conditions specified in
this Agreement, which conditions are intended to ensure compliance with the
provisions of the Securities Act. Each Holder or transferee will cause any
proposed purchaser, assignee, transferee, or pledgee of any such shares held by
the Holder or transferee to agree to take and hold such securities subject to
the restrictions and upon the conditions specified in this Agreement.

     3.   Restrictive Legend. Each certificate representing the Preferred Stock,
          ------------------
the Conversion Stock or any other securities issued in respect of such stock
upon any stock split, stock

                                                                             -3-
<PAGE>

dividend, recapitalization, merger, or similar event, shall (unless otherwise
permitted by the provisions of Section 4 below) be stamped or otherwise
imprinted with legends in substantially the following form (in addition to any
legends required by agreement or by applicable state securities laws):

          THE SECURITIES REPRESENTED HEREBY HAVE NOT BEEN REGISTERED UNDER THE
          SECURITIES ACT OF 1933, AS AMENDED (THE "ACT"). SUCH SECURITIES MAY
          NOT BE TRANSFERRED UNLESS A REGISTRATION STATEMENT UNDER THE ACT IS IN
          EFFECT AS TO SUCH TRANSFER OR IN THE OPINION OF COUNSEL FOR THE
          COMPANY, SUCH TRANSFER MAY BE MADE PURSUANT TO RULE 144 OR
          REGISTRATION UNDER THE ACT IS OTHERWISE UNNECESSARY IN ORDER FOR SUCH
          TRANSFER TO COMPLY WITH THE ACT.

          THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO A LOCKUP
          PERIOD OF UP TO 180 DAYS FOLLOWING THE EFFECTIVE DATE OF A
          REGISTRATION STATEMENT OF THE COMPANY FILED UNDER THE SECURITIES ACT
          OF 1933, AS AMENDED, AS SET FORTH IN AN AGREEMENT BETWEEN THE ISSUER
          AND THE ORIGINAL HOLDER OF THESE SHARES, A COPY OF WHICH MAY BE
          OBTAINED AT THE PRINCIPAL OFFICE OF THE ISSUER. SUCH LOCKUP PERIOD IS
          BINDING ON TRANSFEREES OF THESE SHARES.

          Each Holder consents to the Company making a notation on its records
and giving stop transfer instructions to any transfer agent of its capital stock
in order to implement the restrictions on transfer established in this
Agreement.

     4.   Notice of Proposed Transfers. The holder of each certificate
          ----------------------------
representing Restricted Securities by acceptance thereof agrees to comply in all
respects with the provisions of this Section 4. Without in any way limiting the
immediately preceding sentence, no sale, assignment, transfer or pledge of
Restricted Securities shall be made by any holder thereof to any person unless
such person shall first agree in writing to be bound by the restrictions of this
Agreement. Prior to any proposed sale, assignment, transfer or pledge of any
Restricted Securities, unless there is in effect a registration statement under
the Securities Act covering the proposed transfer, the holder thereof shall give
written notice to the Company of such holder's intention to effect such
transfer, sale, assignment or pledge. Each such notice shall describe the manner
and circumstances of the proposed transfer, sale, assignment or pledge in
sufficient detail, and, if requested by the Company, the holder shall also
provide, at such holder's expense, either (i) a written opinion of legal counsel
who shall be, and whose legal opinion shall be, reasonably satisfactory to the
Company addressed to the Company, to the effect that the proposed transfer of
the Restricted Securities may be effected without registration under the
Securities Act, or (ii) a "no action" letter from the Commission to the

                                                                             -4-
<PAGE>

effect that the transfer of such securities without registration will not result
in a recommendation by the staff of the Commission that action be taken with
respect thereto, whereupon the holder of such Restricted Securities shall be
entitled to transfer such Restricted Securities in accordance with the terms of
the notice delivered by the holder to the Company; provided, however, that the
Company shall not request an opinion of counsel or "no action" letter with
respect to (i) a transfer not involving a change in beneficial ownership, (ii) a
transaction involving the distribution without consideration of Restricted
Securities by the holder to its constituent partners or members in proportion to
their ownership interests in the holder, or (iii) a transaction involving the
transfer without consideration of Restricted Securities by an individual holder
during such holder's lifetime by way of gift or on death by will or intestacy.
Each certificate evidencing the Restricted Securities transferred as above
provided shall bear, except if such transfer is made pursuant to Rule 144, the
appropriate restrictive legend set forth in Section 3 above, except that such
certificate shall not bear such restrictive legend if in the opinion of counsel
for such holder and counsel for the Company such legend is not required in order
to establish compliance with any provision of the Securities Act.
Notwithstanding the foregoing, each holder of Restricted Securities agrees that
it will not request that a transfer of the Restricted Securities be made or that
the legend set forth in Section 3 be removed from the certificate representing
the Restricted Securities, solely in reliance on Rule 144(k), if as a result
thereof the Company would be rendered subject to the reporting requirements of
the Exchange Act.

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

          5.1  Requested Registration.
               ----------------------

               (a)  Request for Registration. In case the Company shall receive
from Initiating Holders a written request that the Company effect any
registration with respect to shares of Registrable Securities, the Company will:

                    (i)  promptly give written notice of the proposed
registration to all other Holders; and

                    (ii) as soon as practicable, use commercially reasonable
efforts to effect such registration as part of a firm commitment underwritten
public offering with underwriters reasonably acceptable to the Initiating
Holders and the Company (including, without limitation, appropriate
qualification under applicable state securities laws and appropriate compliance
with applicable regulations issued under the Securities Act and any other
governmental requirements or regulations) as may be so requested and as would
permit or facilitate the sale and distribution of all or such portion of such
Registrable Securities as are specified in such request, together with all or
such portion of the Registrable Securities of any Holder or Holders joining in
such request by delivering a written notice to such effect to the Company within
twenty days after the date of such written notice from the Company.

                                                                             -5-
<PAGE>

     Notwithstanding the foregoing, the Company shall not be obligated to take
any action to effect or complete any such registration pursuant to this Section
5.1:

                              (A) Prior to the earlier of (i) one year after the
effective date of the Company's first registered public offering of its Common
Stock or (ii) five years from the date hereof;

                              (B) Unless the requested registration would have
an aggregate offering price of all Registrable Securities sought to be
registered by all Holders, net of underwriting discounts and commissions,
exceeding $5,000,000;

                              (C) Following the filing of, and for 180 days
immediately following the effective date of, any registration statement
pertaining to securities of the Company (other than a registration of securities
in a Rule 145 transaction or with respect to an employee benefit plan), provided
that the Company is actively employing in good faith commercially reasonable
efforts to cause such registration statement to become effective;

                              (D) After the Company has effected
two registrations pursuant to this Section 5.1(a) in which the Initiating
Holders were able to sell at least 50% of the Registrable Securities sought to
be included and such registration has been declared or ordered effective;

                              (E) If the Initiating Holders are able to request
a registration on Form S-3 pursuant to Section 5.3 hereof;

                              (F) Within twelve months after the Company has
effected such a registration pursuant to this Section 5.1(a), and such
registration has been declared or ordered effective; or

                              (G) If the Company shall furnish to the Initiating
Holders a certificate signed by the President of the Company (i) giving notice
of its bona fide intention to effect the filing of a registration statement with
the Commission, or (ii) stating that in the good faith judgment of the Board of
Directors it would be seriously detrimental to the Company or its stockholders
for a registration statement to be filed in the near future. In such case, the
Company's obligation to use its commercially reasonable efforts to register,
qualify or comply under this Section 5.1(a) shall be deferred one or more times
for a period not to exceed 180 days from the receipt of the request to file such
registration by such Initiating Holder or Holders, provided that the Company may
not exercise this deferral right more than once per twelve month period.

     Subject to the foregoing clauses (A) through (G), the Company shall file a
registration statement covering the Registrable Securities so requested to be
registered as soon as practicable after receipt of the request or requests of
the Initiating Holders.

                                                                             -6-
<PAGE>

               (b) Underwriting. In the event of a registration pursuant to
Section 5.1, the Company shall advise the Holders as part of the notice given
pursuant to Section 5.1(a)(i) that the right of any Holder to registration
pursuant to Section 5.1 shall be conditioned upon such Holder's participation in
the underwriting arrangements required by this Section 5.1, and the inclusion of
such Holder's Registrable Securities in the underwriting to the extent requested
shall be limited to the extent provided herein.

     The Company shall, together with all Holders proposing to distribute their
securities through such underwriting, enter into an underwriting agreement in
customary form with the managing underwriter selected for such underwriting by a
majority in interest of the Initiating Holders, but subject to the Company's
reasonable approval. Notwithstanding any other provision of this Section 5.1, if
the managing underwriter determines that marketing factors require a limitation
of the number of shares to be underwritten, the managing underwriter may limit
the Registrable Securities to be included in such registration (i) in the case
of the Company's initial public offering, to zero, and (ii) in the case of any
other offering, to an amount no less than 33% of all shares to be included in
such offering. The Company shall so advise all Holders requesting to be included
in the registration and underwriting and the number of shares of Registrable
Securities that may be included in the registration and underwriting shall be
allocated among all Holders requesting to be included in the registration and
underwriting in proportion, as nearly as practicable, to the respective amounts
of Registrable Securities held by them at the time of filing the registration
statement. No Registrable Securities excluded from the underwriting by reason of
the underwriter's marketing limitation shall be included in such registration.
To facilitate the allocation of shares in accordance with the above provisions,
the Company or the underwriters may round the number of shares allocated to any
Holder to the nearest 100 shares. If any Holder of Registrable Securities
disapproves of the terms of the underwriting, such person may elect to withdraw
therefrom by written notice to the Company.

          5.2  Company Registration.
               --------------------

               (a)  Notice of Registration. If at any time or from time to time
                    ----------------------
the Company shall determine to register any of its equity securities, either for
its own account or the account of a Holder or other holders, other than (i) a
registration relating solely to employee benefit plans, (ii) a registration
relating solely to a Rule 145 transaction, or (iii) a registration in which the
only equity security being registered is Common Stock issuable upon conversion
of convertible debt securities which are also being registered, the Company
will:
                    (i)  promptly give to each Holder written notice thereof;
and

                    (ii) include in such registration (and any related
qualifications including compliance with Blue Sky laws), and in any underwriting
involved therein, all the Registrable Securities specified in a written request
or requests, made within ten days after the date of such written notice from the
Company, by any Holder.

                                                                             -7-
<PAGE>

               (b)  Underwriting. If the registration of which the Company gives
                    ------------
notice is for a registered public offering involving an underwriting, the
Company shall so advise the Holders as a part of the written notice given
pursuant to Section 5.2(a)(i). In such event, the right of any Holder to
registration pursuant to Section 5.2 shall be conditioned upon such Holder's
participation in such underwriting and the inclusion of Registrable Securities
in the underwriting shall be limited to the extent provided herein.

          All Holders proposing to distribute their securities through such
underwriting shall (together with the Company and the other Holders distributing
their securities through such underwriting) enter into an underwriting agreement
in customary form with the managing underwriter selected for such underwriting
by the Company. Notwithstanding any other provision of this Section 5.2, if the
managing underwriter determines that marketing factors require a limitation of
the number of shares to be underwritten, the managing underwriter may limit the
Registrable Securities to be included in such registration (i) in the case of
the Company's initial public offering, to zero, and (ii) in the case of any
other offering, to an amount no less than 33% of all shares to be included in
such offering. The Company shall so advise all Holders requesting to be included
in the registration and underwriting and the number of shares of Registrable
Securities that may be included in the registration and underwriting shall be
allocated among all the Holders requesting to be included in the registration
and underwriting in proportion, as nearly as practicable, to the respective
amounts of Registrable Securities held by them at the time of filing the
registration statement. To facilitate the allocation of shares in accordance
with the above provisions, the Company or the underwriters may round the number
of shares allocated to any Holder to the nearest 100 shares. If any Holder
disapproves of the terms of any such underwriting, such person may elect to
withdraw therefrom by written notice to the Company.

               (c)  Right to Terminate Registration. The Company shall have the
                    -------------------------------
right to terminate or withdraw any registration initiated by it under this
Section 5.2 prior to the effectiveness of such registration whether or not any
Holder has elected to include securities in such registration.

          5.3  Registration on Form S-3.
               ------------------------

               (a)  Request for Registration. In case the Company shall receive
                    ------------------------
from Initiating Holders a written request that the Company file a registration
statement on Form S-3 (or any successor form to Form S-3) for a public offering
of shares of the Registrable Securities the aggregate price to the public of
which, net of underwriting discounts and commissions, would exceed $3,000,000,
and the Company is a registrant entitled to use Form S-3 to register the
Registrable Securities for such an offering, the Company shall use commercially
reasonable efforts to cause such Registrable Securities to be registered for the
offering on such form and to cause such Registrable Securities to be qualified
in such jurisdictions as such Holder or Holders may reasonably request;
provided, however, that the Company shall not be required to effect more than
one registration pursuant to this Section 5.3 in any twelve month period. If
such offer is to be an underwritten offer, the underwriters must be acceptable
to both the Initiating Holders and the Company. The Company shall inform the
other Holders of the proposed registration and offer them

                                                                             -8-
<PAGE>

the opportunity to participate. In the event the registration is proposed to be
part of a firm commitment underwritten public offering, the substantive
provisions of Section 5.1(b) shall be applicable to each such registration
initiated under this Section 5.3.

               (b)  Notwithstanding the foregoing, the Company shall not be
obligated to take any action pursuant to this Section 5.3:

                    (i)   Following the filing of, and for 180 days immediately
following the effective date of, any registration statement pertaining to
securities of the Company (other than a registration of securities in a Rule 145
transaction or with respect to an employee benefit plan), provided that the
Company is actively employing in good faith commercially reasonable efforts to
cause such registration statement to become effective;

                    (ii)  Within twelve months after the Company has effected
such a registration pursuant to this Section 5.3(a), and such registration has
been declared or ordered effective; or

                    (iii) If the Company shall furnish to the Initiating Holders
a certificate signed by the President of the Company (i) giving notice of its
bona fide intention to effect the filing of a registration statement with the
Commission, or (ii) stating that, in the good faith judgment of the Board of
Directors, it would be seriously detrimental to the Company or its stockholders
for a registration statement to be filed in the near future, then the Company's
obligation to use its commercially reasonable efforts to file a registration
statement shall be deferred one or more times for a period not to exceed 180
days from the receipt of the request to file such registration by such
Initiating Holder or Holders, provided that the Company may not exercise this
deferral right more than once per twelve month period.

          5.4  Subsequent Registration Rights.
               ------------------------------

               (a)  Without the consent of any holder of Registrable Securities
hereunder, the Company may grant to any holder of securities of the Company
registration rights inferior to those granted hereunder.

               (b)  The Company shall not enter into any agreement granting any
holder or prospective holder of any securities of the Company registration
rights superior to or on a pari passu basis with the rights granted the Holders
hereunder without the written consent of the holders of a majority of the
Registrable Securities. Notwithstanding the foregoing, the Company may, without
obtaining any further consent of the holders of Registrable Securities, amend
this Agreement to the extent necessary to grant rights and obligations on a pari
passu basis with the rights and obligations of the Holders to investors in any
subsequent round of financing with respect to the securities purchased by such
investors in such financing.

                                                                             -9-
<PAGE>

          5.5  Expenses of Registration. All Registration Expenses incurred in
               ------------------------
connection with (i) two registrations pursuant to Section 5.1, (ii) all
registrations pursuant to Section 5.2, and (iii) all registrations pursuant to
Section 5.3, shall be borne by the Company. Notwithstanding the foregoing, in
the event that Initiating Holders cause the Company to begin a registration
pursuant to Section 5.1, and the request for such registration is subsequently
withdrawn by the Initiating Holders or such registration is not completed due to
failure to meet the net proceeds requirement set forth in such section or is
otherwise not successfully completed due to no fault of the Company, all Holders
shall be deemed to have forfeited their right to one registration under Section
5.1 unless the Initiating Holders pay for, or reimburse the Company for, the
Registration Expenses incurred in connection with such withdrawn or incomplete
registration. Unless otherwise stated, all Selling Expenses relating to
securities registered on behalf of the Holders and all other registration
expenses shall be borne by the Holders of such securities pro rata on the basis
of the number of shares so registered or proposed to be so registered.

          5.6  Registration Procedures. In the case of each registration
               -----------------------
effected by the Company pursuant to this Agreement, the Company will keep each
Holder advised in writing as to the initiation of such registration and as to
the completion thereof. The Company will:

               (a) Prepare and file with the Commission a registration statement
and such amendments and supplements as may be necessary and use commercially
reasonable efforts to cause such registration statement to become and remain
effective for at least 90 days or until the distribution described in the
registration statement has been completed, whichever first occurs; provided,
however, that such 90 day period shall be extended for a period of time equal to
that which the Holder refrains from selling any securities at the request of any
underwriter of the Company; and

               (b) Furnish to the Holders participating in such registration and
to the underwriters of the securities being registered such reasonable number of
copies of the registration statement, preliminary prospectus, final prospectus
and such other documents as such underwriters may reasonably request in order to
facilitate the public offering of such securities.

          5.7  Indemnification.
               ---------------

               (a) The Company will indemnify each Holder, each of its officers
and directors and partners, and each person controlling such Holder within the
meaning of Section 15 of the Securities Act, with respect to which registration
has been effected pursuant to this Agreement, against all expenses, claims,
losses, damages or liabilities (or actions in respect thereof), including any of
the foregoing incurred in settlement of any litigation, commenced or threatened,
arising out of or based on any untrue statement (or alleged untrue statement) of
a material fact contained in any registration statement, prospectus, offering
circular or other document, or any amendment or supplement thereto, incident to
any such registration, or based on any omission (or alleged omission) to state
therein a material fact required to be stated therein or necessary to make the
statements therein, in light of the circumstances in which they were made, not
misleading, or any violation by the Company of the Securities Act, the Exchange
Act, state securities laws or any rule or regulation

                                                                            -10-
<PAGE>

promulgated under such laws applicable to the Company in connection with any
such registration, and the Company will reimburse each such Holder, each of its
officers and directors, and each person controlling such Holder, for any legal
and any other expenses reasonably incurred, as such expenses are incurred, in
connection with investigating, preparing or defending any such claim, loss,
damage, liability or action, provided that the Company will not be liable in any
such case to the extent that any such claim, loss, damage, liability or expense
arises out of or is based on any untrue statement or omission or alleged untrue
statement or omission, made in reliance upon and in conformity with written
information furnished to the Company by an instrument duly executed by such
Holder or controlling person, and stated to be specifically for use therein;
provided, however, that the foregoing indemnity Agreement is subject to the
condition that, insofar as it relates to any such untrue statement, alleged
untrue statement, omission or alleged omission made in a preliminary prospectus
on file with the Commission at the time the registration statement becomes
effective or the amended prospectus is filed with the Commission pursuant to
Rule 424(b) (the "Final Prospectus"), such indemnity Agreement shall not inure
to the benefit of any Holder, if a copy of the Final Prospectus was not
furnished to the person asserting the loss, liability, claim or damage at or
prior to the time such action is required by the Securities Act, and if the
Final Prospectus would have cured the defect giving rise to the loss, liability,
claim or damage.

               (b)  Each Holder will, if Registrable Securities held by such
Holder are included in the securities as to which such registration is being
effected, indemnify the Company, each of its directors and officers, other
holders of the Company's securities covered by such registration statement, each
person who controls the Company within the meaning of Section 15 of the
Securities Act, and each other such Holder, each of its officers and directors
and each person controlling such Holder within the meaning of Section 15 of the
Securities Act, against all claims, losses, damages and liabilities (or actions
in respect thereof) arising out of or based on any untrue statement (or alleged
untrue statement) of a material fact contained in any such registration
statement, prospectus, offering circular or other document, or any omission (or
alleged omission) to state therein a material fact required to be stated therein
or necessary to make the statements therein not misleading, or any violation by
the Holder of the Securities Act, the Exchange Act, state securities laws or any
rule or regulation promulgated under such laws applicable to the Holder, and
will reimburse the Company, such other Holders, such directors, officers,
persons, underwriters or control persons for any legal or any other expenses
reasonably incurred, as such expenses are incurred, in connection with
investigating or defending any such claim, loss, damage, liability or action,
but in the case of the Company or the other Holders or their officers, directors
or controlling persons, only to the extent that such untrue statement (or
alleged untrue statement) or omission (or alleged omission) is made in such
registration statement, prospectus, offering circular or other document in
reliance upon and in conformity with information furnished to the Company by
such Holder. Notwithstanding the foregoing, the liability of each Holder under
this subsection 5.7(b) shall be limited in an amount equal to the initial public
offering price of the shares sold by such Holder, unless such liability arises
out of or is based on willful misconduct or fraud by such Holder.

                                                                            -11-
<PAGE>

               (c)  Each party entitled to indemnification under this Section
5.7 (the "Indemnified Party") shall give notice to the party required to provide
indemnification (the "Indemnifying Party") promptly after such Indemnified Party
has actual knowledge of any claim as to which indemnity may be sought, and shall
permit the Indemnifying Party to assume the defense of any such claim or any
litigation resulting therefrom, provided that counsel for the Indemnifying
Party, who shall conduct the defense of such claim or litigation, shall be
approved by the Indemnified Party (whose approval shall not unreasonably be
withheld), and the Indemnified Party may participate in such defense at such
party's expense, and provided further that the failure of any Indemnified Party
to give notice as provided herein shall not relieve the Indemnifying Party of
its obligations under this Agreement unless the failure to give such notice is
materially prejudicial to an Indemnifying Party's ability to defend such action
and provided further, that the Indemnifying Party shall not assume the defense
for matters as to which there is a conflict of interest or there are separate
and different defenses. No Indemnifying Party, in the defense of any such claim
or litigation, shall, except with the consent of each Indemnified Party (whose
consent shall not be unreasonably withheld), consent to entry of any judgment or
enter into any settlement which does not include as an unconditional term
thereof the giving by the claimant or plaintiff to such Indemnified Party of a
release from all liability in respect to such claim or litigation.

               (d)  Notwithstanding the foregoing, to the extent that the
provisions on indemnification and contribution contained in the underwriting
agreement entered into in connection with the underwritten public offering are
in conflict with the foregoing provisions, the provisions in the underwriting
agreement shall control.


          5.8  Information by Holder. The Holder or Holders of Registrable
               ---------------------
Securities included in any registration shall furnish to the Company such
information regarding such Holder or Holders, the Registrable Securities held by
them and the distribution proposed by such Holder or Holders as the Company may
request in writing and as shall be required in connection with any registration
referred to in this Agreement.

          5.9  Rule 144 Reporting. With a view to making available the benefits
               ------------------
of certain rules and regulations of the Commission which may at any time permit
the sale of the Restricted Securities to the public without registration, after
such time as a public market exists for the Common Stock of the Company, the
Company agrees to use commercially reasonable efforts to:

               (a)  Make and keep public information available, as those terms
are understood and defined in Rule 144 under the Securities Act, at all times
after the effective date that the Company becomes subject to the reporting
requirements of the Securities Act or the Exchange Act;

               (b)  File with the Commission in a timely manner all reports and
other documents required of the Company under the Securities Act and the
Exchange Act (at any time after it has become subject to such reporting
requirements); and

                                                                            -12-
<PAGE>

               (c)  So long as a Holder owns any Restricted Securities, to
furnish to the Holder forthwith upon request a written statement by the Company
as to its compliance with the reporting requirements of said Rule 144 (at any
time after 90 days after the effective date of the first registration statement
filed by the Company for an offering of its securities to the general public), a
copy of the most recent annual or quarterly report of the Company, and such
other reports and documents of the Company and other information in the
possession of or reasonably obtainable by the Company as the Holder may
reasonably request in availing itself of any rule or regulation of the
Commission allowing the Holder to sell any such securities without registration.

          5.10 Termination of Registration Rights. The rights granted pursuant
               ----------------------------------
to Sections 5.1, 5.2 and 5.3 of this Agreement shall terminate as to any Holder
upon the earlier of (i) the date four years after the effective date of the
Company's initial public offering and (ii) the date such Holder is able to
immediately sell all shares of Registrable Securities held or entitled to be
held upon conversion by such Holder under Rule 144 during any 90-day period.

     6.   Financial Information Rights.
          ----------------------------

               (a)  The Company will, upon request, provide the following
documents to each Holder who continues to hold at least the lesser of (A)
1,000,000 shares of Preferred Stock and/or Conversion Stock (as adjusted for
recapitalizations, stock combinations, stock dividends, stock splits and the
like) or (B) fifty percent (50%) of the shares of Preferred Stock and/or
Conversion Stock initially acquired by such Holder (as adjusted for
recapitalizations, stock combinations, stock dividends, stock splits and the
like):

                    (i)   As soon as practicable after the end of the fiscal
year ending December 31, 1998 and each fiscal year thereafter, and in any event
within 90 days after the end of each such fiscal year, consolidated balance
sheets of the Company and its subsidiaries, if any, as of the end of such fiscal
year, and consolidated statements of operations and consolidated statements of
cash flows and stockholders' equity of the Company and its subsidiaries, if any,
for such year, prepared in accordance with generally accepted accounting
principles and setting forth in each case in comparative form the figures for
the previous fiscal year (except that no such comparative data from the fiscal
year ended December 31, 1997 need be provided), all in reasonable detail and
audited by independent public accountants of national standing selected by the
Company, and a capitalization table in reasonable detail for such fiscal year;

                    (ii)  As soon as practicable after the end of each monthly
accounting period in each fiscal year of the Company and in any event within 30
days after, a consolidated balance sheet of the Company and its subsidiaries, if
any, as of the end of each such quarterly period, and consolidated statements of
operations and consolidated statements of cash flows of the Company and its
subsidiaries, if any, for such period and for the current fiscal year to date,
prepared in accordance with generally accepted accounting principles (other than
accompanying notes), subject to changes resulting from year-end audit
adjustments, in reasonable detail and signed by the principal financial or
accounting officer of the Company, and a

                                                                            -13-
<PAGE>

capitalization table in reasonable detail for such quarterly period, and such
other documents generally distributed or made available to the Company's
stockholders; provided, however, that the Company shall not be obligated to
provide information which it deems in good faith to be proprietary or
confidential.

                    (iii) such other documents generally distributed or made
available to the Company's stockholders; provided, however, that the Company
                                         --------  -------
shall not be obligated to provide information which it deems in good faith to be
proprietary or confidential.

               (b)  For purposes of determining the minimum holdings pursuant to
this Section 6, any Purchaser which is a partnership or limited liability
company shall be deemed to hold any Preferred Stock originally purchased by such
Holder and subsequently distributed to constituent partners or members of such
Holder, but which have not been resold by such partners or members. If the
partnership or limited liability company is still in existence, the Company may
satisfy any obligation to distribute reports to individual partners of the
partnership or members of a limited liability company by delivering a single
copy of each report to the partnership or limited liability company as agent for
the constituent partners or members.

               (c)  Each Holder or transferee of rights under this Section 6
acknowledges and agrees that any information obtained pursuant to this Section 6
which may be considered nonpublic information will be maintained in confidence
by such Holder or transferee and will not be utilized by such Holder or
transferee in connection with purchases or sales of the Company's securities
except in compliance with applicable state and Federal securities laws.

               (d)  The covenants of the Company set forth in this Section 6
shall terminate and be of no further force or effect upon the earliest to occur
of (i) the closing of a Qualified Initial Public Offering; or (ii) the sale of
all or substantially all of the assets of the Company or the acquisition of the
Company by another entity by means of merger or consolidation resulting in the
exchange of the outstanding shares of the Company for securities or
consideration issued, or caused to be issued, by the acquiring corporation or
its subsidiary, unless the stockholders of the Company hold at least fifty
percent (50%) of the voting power of the surviving corporation in such a
transaction.

     7.   Lockup Agreement. Each Holder and transferee hereby agrees that, in
          ----------------
connection with the first two registrations of the offering of any securities of
the Company under the Securities Act for the account of the Company, if so
requested by the Company or any representative of the underwriters (the
"Managing Underwriter"), such Holder or transferee shall not sell or otherwise
transfer any securities of the Company during the period specified by the
Company's Board of Directors at the request of the Managing Underwriter (the
"Market Standoff Period"), with such period not to exceed (i) 180 days following
the effective date of a registration statement of the Company filed under the
Securities Act. The Company may impose stop-transfer instructions with respect
to securities subject to the foregoing restrictions until the end of such Market
Standoff Period. The Company shall use commercially reasonable efforts to place
similar contractual lockup

                                                                            -14-
<PAGE>

restrictions on all capital stock issued now or hereafter to officers,
directors, employees and consultants of the Company and holders of registration
rights with respect to capital stock of the Company.

     8.   Right of First Refusal.
          ----------------------

               (a)  The Company hereby grants to idealab! Holdings, L.L.C.
("idealab"), MSD Portfolio L.P. -Investments, Susan L. Dell Separate Property
Trust, Black Marlin Investments, LLC, Vermear Investments, LLC, Victory
Partners - A, L.P., the Goldman Sachs Group, L.P., Stone Street Fund 1999, L.P.
and Bridge Street Fund 1999, L.P. (the "Qualified Purchasers") the right of
first refusal to purchase its Pro Rata Share of New Securities (as defined in
Section 8(d)) which the Company may, from time to time, propose to sell and
issue. A "Pro Rata Share," for purposes of this right of first refusal, equals
the proportion that the total number of shares of Common Stock then held by the
Qualified Purchasers plus the number of shares of Common Stock issuable upon
conversion of the Series A Preferred Stock, the Series C Preferred Stock and the
Series D Preferred Stock then held by the Qualified Purchasers bears to the sum
of the total number of shares of Common Stock then outstanding plus the number
of shares of Common Stock issuable upon exercise or conversion of all then
outstanding securities exercisable for or convertible into, directly or
indirectly, Common Stock.

               (b)  Subject to the rights of all Qualified Purchasers (other
than idealab) as set forth in Section 8(a), in connection with one or more
equity financings of the Company subsequent to the date of this Agreement
pursuant to which New Securities (as defined in Section 8(d) except that for
purposes of this Section 8(b), New Securities shall include capital stock issued
or issuable in the Company's Qualified Initial Public Offering) are issued (a
"Subsequent Financing"), the Company hereby covenants to provide idealab the
right to purchase an amount of New Securities that would enable idealab to own
following such Subsequent Financing 38.2% of the Common Stock of the Company (on
a fully diluted as converted to Common Stock basis) (the "Purchase Right"). In
the event that the Subsequent Financing is the Company's Qualified Initial
Public Offering, the Purchase Right shall be reduced or eliminated if the
Managing Underwriter determines, in its sole discretion, that the exercise of
the Purchase Right would adversely impact the Qualified Initial Public Offering.

               (c)  If the Company intends to commence a Subsequent Financing,
the Company shall deliver to idealab a written notice (the "Written
Notification") stating: (i) its bona fide intention to commence a Subsequent
Financing; (ii) the then projected amount of money to be raised by the Company
in the Subsequent Financing; and (iii) if then known, the projected per share
price of the capital stock sold in the Subsequent Financing. idealab's Purchase
Right shall then be exercisable for ten (10) days after the date of the Written
Notification. idealab shall exercise its Purchase Right by delivering to the
Company a written notice indicating the number of shares (or percentage of the
shares of Common Stock of the Company on a post-Subsequent Financing fully
diluted as converted to Common Stock basis) pursuant to the Purchase Right that
it elects to purchase.

                                                                            -15-
<PAGE>

               If idealab elects to exercise its Purchase Right, its obligations
to the Company will not exceed the amount it elected to purchase based upon (i)
the projected amount of money to be raised by the Company in the Subsequent
Financing; and (ii) the projected per share price of the capital stock in the
Subsequent Financing that were stated in the Written Notification.

          If idealab elects to exercise its Purchase Right, such purchase of
shares of capital stock shall be on the same terms and conditions as the other
purchasers of shares of capital stock in the Subsequent Financing at the time of
the first closing of the Subsequent Financing. If the Subsequent Financing is
the Company's Qualified Initial Public Offering, such purchase of shares of
capital stock shall be at the purchase price paid by the public. If the
Subsequent Financing does not close within six (6) months after the date of the
Written Notification, then idealab's exercise of its Purchase Right shall be
null and void and idealab shall not be obligated, but may elect, to purchase
shares of capital stock in the Subsequent Financing.

               (d)  Except as set forth below, "New Securities" shall mean any
shares of capital stock of the Company, including Common Stock and any series of
preferred stock, whether now authorized or not, and rights, options or warrants
to purchase said shares of Common Stock or preferred stock, and securities of
any type whatsoever that are, or may become, convertible into or exchangeable
for said shares of Common Stock or preferred stock. Notwithstanding the
foregoing, "New Securities" does not include stock issued and issuable: (i) upon
conversion of shares of Preferred Stock; (ii) to employees, consultants or
directors pursuant to stock options, stock grants, or stock purchase rights
under the Company's 1998 Stock Option Plan approved by the Board of Directors,
including without limitation upon the exercise of Options outstanding as of the
Original Issue Date, or any such options, grants or rights made outside of such
plan to any person or group (provided that any such non-plan options, grants, or
rights do not exceed 200,000 shares (as adjusted for stock splits and the like)
per person or group of affiliated persons in one transaction or a series of
related transactions); (iii) to equipment lessors, banks financial institutions
or similar entities in a transaction approved by the board of directors, the
principle purpose of which is other than the raising of capital; (iv) as a
dividend or other distribution; (v) in the Company's Qualified Initial Public
Offering; (vi) in a merger or acquisition that is approved by the Board of
Directors; (vii) pursuant to any transactions approved by the Board of Directors
primarily for the purpose of (A) joint ventures, technology licensing or
research and development activities, (B) distribution or manufacture of the
Company's products or service, or (C) any other transactions involving corporate
partners that are primarily for purposes other than raising capital; or (viii)
if the holders of a majority of the then outstanding Registrable Securities
agree in writing that such shares shall not constitute New Securities.

               (e)  In the event the Company proposes to undertake an issuance
of New Securities, it shall give the Qualified Purchaser written notice of its
intention, describing the amount and type of New Securities, and the price and
terms upon which the Company proposes to issue the same. The Qualified Purchaser
shall have ten days from the date of receipt of any such notice to agree to
purchase up to its Pro Rata Share of such New Securities for the price and upon
the terms

                                                                            -16-
<PAGE>

specified in the notice by giving written notice to the Company and stating
therein the quantity of New Securities to be purchased.

               (f)  Beginning ten days after the notice given pursuant to
Section 8(b) above, the Company shall have 180 days to sell the New Securities
not elected or eligible to be purchased by the Qualified Purchaser at the price
and upon the terms no more favorable to the purchasers of such securities than
specified in the Company's notice. In the event the Company has not sold all of
the New Securities within said 180 day period, the Company shall not thereafter
issue or sell any New Securities without first offering such securities in the
manner provided above.

               (g)  The provisions of Sections 8(a), (c), (d), (e) and (f) will
terminate and be of no further force or effect upon the earlier to occur of: (i)
the closing of a Qualified Initial Public Offering, or (ii) the sale of all or
substantially all of the assets of the Company or the acquisition of the Company
by another entity by means of merger or consolidation resulting in the exchange
of the outstanding shares of the Company for securities or consideration issued,
or caused to be issued, by the acquiring corporation or its subsidiary, unless
the stockholders of the Company hold at least fifty percent (50%) of the voting
power of the surviving corporation in such a transaction.

               (h)  The provisions of Section 8(b) will terminate and be of no
further force or effect (i) following (but not including) the closing of a
Qualified Initial Public Offering, or (ii) the sale of all or substantially all
of the assets of the Company or the acquisition of the Company by another entity
by means of merger or consolidation resulting in the exchange of the outstanding
shares of the Company for securities or consideration issued, or caused to be
issued, by the acquiring corporation or its subsidiary, unless the stockholders
of the Company hold at least fifty percent (50%) of the voting power of the
surviving corporation in such a transaction.

          The provisions of Section 8(a), (c), (d), (e), (f) and (g) may be
amended only with the written consent of the Qualified Purchasers of the Company
and the provisions of Section 8(b) and (h) may be amended only with the written
consent of idealab and the Company.

     9.   Vesting of Employee Options. Unless otherwise agreed to by a majority
          ---------------------------
of the Directors who are not then employees of the Company, options granted to
employees of the Company under the Company's 1998 Employee Stock Plan or other
approved stock plans will vest, until the option holder's employment with or
service to the Company terminates, on terms no more favorable to the employee
than twenty percent (20%) of such shares on the date of employment and twenty
percent (20%) of such shares at the end of each year for four (4) years
thereafter.

     10.  Employment, Confidential Information and Invention Assignment
          -------------------------------------------------------------
Agreements. The Company will maintain a policy requiring each person now or
----------
hereafter employed by it or any subsidiary with access to confidential
information to enter into an Employment, Confidential Information and Invention
Assignment Agreement substantially in a form approved by the Board of Directors.

                                                                            -17-
<PAGE>

     11.  Transfer of Rights. The rights granted under Sections 5, 6 and 8 of
          ------------------
this Agreement may be assigned to any transferee or assignee, other than a
competitor or potential competitor of the Company (as determined in good faith
by the Company's Board of Directors in connection with any transfer or
assignment of Registrable Securities by the Holder, provided that: (i) such
transfer is otherwise effected in accordance with applicable securities laws and
the terms of this Agreement; (ii) such assignee or transferee acquires at least
the lesser of (A) 1,000,000 shares (as adjusted for stock splits, stock
dividends, stock combinations and the like) of Registrable Securities (including
Preferred Stock convertible into Registrable Securities) or (B) fifty percent
(50%) of the shares of Registrable Securities (as adjusted for stock splits,
stock dividends, stock combinations and the like) initially acquired by the
transferring Holder (including Preferred Stock convertible into Registrable
Securities), (iii) written notice is promptly given to the Company; and (iv)
such transferee or assignee agrees to be bound by the provisions of this
Agreement. Notwithstanding the foregoing, the rights granted to the Purchaser
hereunder may be assigned without compliance with item (ii) above to any
constituent partner or member of the Purchaser which is a partnership or limited
liability company, or to an affiliate (as such term is defined in Rule 405 of
the Securities Act) of the Purchaser which is a corporation, partnership or
limited liability company.

     12.  Series B Preferred Board Members.  For so long as the holders of
          --------------------------------
Series B Preferred Stock shall be entitled to elect two directors under the
Company's Amended and Restated Certificate of Incorporation, the Purchasers
will: (i) vote for the nominee selected by idealab! Capital Partners I-B, L.P.
provided that idealab! Capital Partners I-A, L.P. and idealab! Capital Partners
I-B, L.P. together hold 500,000 shares of Series B Preferred Stock; and (ii)
vote for the nominee selected by Foundation Capital II, L.P. ("Foundation")
provided that Foundation, Foundation Capital II Entrepreneurs Fund, LLC and
Foundation Capital II Principals Fund, LLC together hold 500,000 shares of
Series B Preferred Stock.

          This Section 12 may be amended only with the written consent of
idealab! Capital Partners I-B, L.P., Foundation and the Company.

     13.  Amendment. Except as otherwise provided herein, additional parties may
          ---------
be added to this Agreement, any provision of this Agreement may be amended or
the observance thereof may be waived (either generally or in a particular
instance and either retroactively or prospectively), only with the written
consent of the Company and the Holders of a majority of the Registrable
Securities then outstanding provided that any amendment treats all holders of
Registrable Securities in a similar manner. Any amendment or waiver effected in
accordance with Section 5.4 or Section 13, as applicable, shall be binding upon
each Purchaser, Holder of Registrable Securities at the time outstanding, each
future holder of any of such securities, and the Company.

     14.  Governing Law.  This Agreement shall be governed in all respects by
          -------------
the internal laws of the State of California without regard to conflict of laws
provisions.

     15.  Entire Agreement.  This Agreement constitutes the full and entire
          ----------------
understanding and Agreement among the parties regarding the matters set forth
herein. Except as otherwise expressly

                                                                            -18-
<PAGE>

provided herein, the provisions hereof shall inure to the benefit of, and be
binding upon the successors, assigns, heirs, executors and administrators of the
parties hereto.

     16.  Notices, etc. All notices and other communications required or
          ------------
permitted hereunder shall be in writing and shall be mailed by registered or
certified mail, postage prepaid, or otherwise delivered by facsimile
transmission, by hand or by messenger, addressed:

          (a)  if to a Holder, at such Holder's address as set forth on the
signature page, or at such other address as such Holder shall have furnished to
the Company.

          (b)  if to the Company, to:

               4312 Woodman Avenue, 3/rd/ Floor
               Sherman Oaks, California 91423
               Attn:  Scott Painter
               Chief Executive Officer
               Fax: (818) 808-4887

               or at such other address as the Company shall have furnished to
               the Holders,

with a copy to:

               Wilson Sonsini Goodrich & Rosati
               650 Page Mill Road
               Palo Alto, California 94304-1050
               Attn:  Martin W. Korman, Esq.
                      Michael D. Charney, Esq.
               Fax:   (650) 493-6811

          Each such notice or other communication shall for all purposes of this
Agreement be treated as effective or having been given when delivered if
delivered personally, if sent by facsimile, the first business day after the
date of confirmation that the facsimile has been successfully transmitted to the
facsimile number for the party notified, or, if sent by mail, at the earlier of
its receipt or 72 hours after the same has been deposited in a regularly
maintained receptacle for the deposit of the United States mail, addressed and
mailed as aforesaid.

     17.  Counterparts. This Agreement may be executed in any number of
counterparts, each of which shall be an original and all of which together shall
constitute one instrument.

                                                                            -19-
<PAGE>

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


CARSDIRECT.COM, INC.                      MSD PORTFOLIO L.P.

By: ________________________              By: __________________________
Name: ______________________              Name:_________________________
Title: _____________________              Title: _______________________


                                          SUSAN L. DELL SEPARATE PROPERTY TRUST


                                          By: __________________________
                                          Name:_________________________
                                          Title: _______________________



                                          BLACK MARLIN INVESTMENTS, LLC


                                          By: __________________________
                                          Name:_________________________
                                          Title: _______________________



                                          VERMEER INVESTMENTS, LLC


                                          By: __________________________
                                          Name:_________________________
                                          Title: _______________________

   [Signature Page to Fourth Amended and Restated Investor Rights Agreement]
<PAGE>

                                          VICTORY PARTNERS - A, L.P.


                                          By: ___________________________
                                          Name:__________________________
                                          Title: ________________________


                                          IDEALAB! HOLDINGS, L.L.C.


                                          By: ___________________________
                                          Name:  Marcia Goodstein
                                               --------------------------
                                          Title: ________________________

                                          Address: 130 W. Union Street
                                                   Pasadena, CA 91103


                                          IDEALAB! CAPITAL PARTNERS-I-A, L.P.


                                          By: ___________________________
                                          Name: Bill Elkus
                                               --------------------------
                                          Title: ________________________

                                          Address: 130 W. Union Street
                                                   Pasadena, CA 91103


                                          IDEALAB! CAPITAL PARTNERS-I-B, L.P.


                                          By: ___________________________
                                          Name: Bill Elkus
                                               --------------------------
                                          Title: ________________________

                                          Address: 130 W. Union Street
                                                   Pasadena, CA 91103


   [Signature Page to Fourth Amended and Restated Investor Rights Agreement]
<PAGE>

                                   HARVEY & SANDRA COHEN LIVING TRUST


                                   By:_________________________________
                                   Name: Harvey Cohen
                                         ------------------------------
                                   Title:______________________________

                                   Address: 5035 Andasol Avenue
                                            Encinco, CA 91316

                                   WS INVESTMENT COMPANY 98B

                                   By:_________________________________
                                   Name: Martin W. Korman
                                         ------------------------------
                                   Title: Partner
                                          -----------------------------

                                   Address: 650 Page Mill Road
                                            Palo Alto, CA 94304

                                   Foundation Capital II, L.P.
                                   By Foundation Capital Management II, LLC


                                   By:_________________________________
                                      Manager

                                   Foundation Capital II Principals Fund, LLC
                                   By Foundation Capital Management II, LLC

                                   By:_________________________________
                                      Manager

                                   Foundation Capital II Entrepreneurs Fund, LLC

                                   By Foundation Capital Management II, LLC

                                   By:_________________________________
                                      Manager

                                   ____________________________________
                                   Scott Painter, an individual

   [Signature Page to Fourth Amended and Restated Investor Rights Agreement]
<PAGE>

                                    ___________________________________
                                    Greg Brogger, an individual

                                    ___________________________________
                                    Daniel Alexander, an individual

                                    ___________________________________
                                    Andrew Skarupa, an individual

                                    ___________________________________
                                    Steven Damron, an individual


                                    Emanuel Wasserman DDS MSD APC
                                    Employees' Profit Sharing Plan

                                    By:________________________________
                                    Name:______________________________
                                    Title:_____________________________


                                    Ronald Nussbaum, SSB Keogh
                                    MP Custodian

                                    ___________________________________
                                    Ari Wasserman, an individual

                                    PRIMEDIA VENTURES, INC.

                                    By:________________________________
                                    Name:______________________________
                                    Title:_____________________________


                                    ___________________________________
                                    Marcia Goodstein, an individual

                                    ___________________________________
                                    Judith and David Goodstein

   [Signature Page to Fourth Amended and Restated Investor Rights Agreement]
<PAGE>

                                    WS INVESTMENT COMPANY 99A

                                    By:________________________________
                                    Name:______________________________
                                    Title:_____________________________

                                    THE GOLDMAN SACHS GROUP, L.P.
                                    By: The Goldman Sachs Corporation
                                        its general partner

                                    By:________________________________
                                    Name:______________________________
                                    Title:_____________________________

                                    STONE STREET FUND 1999, L.P.
                                    By: Stone Street 1999 Corp.
                                        its general partner

                                    By:________________________________
                                    Name:______________________________
                                    Title:_____________________________


                                    BRIDGE STREET FUND 1999, L.P.
                                    By: Stone Street 1999 Corp.
                                        its general partner

                                    By:________________________________
                                    Name:______________________________
                                    Title:_____________________________

   [Signature Page to Fourth Amended and Restated Investor Rights Agreement]
<PAGE>

                                   CARSONLINE LLC

                                   By:________________________________
                                   Name: Ahmed O. Alfi
                                        ------------------------------
                                   Title:_____________________________

                                   Address: 301 North Lake Avenue
                                            Suite 910
                                            Pasadena, CA 91101


                                   GBJ HOLDINGS, LLC

                                   By:________________________________
                                   Name: Joel S. Beckman
                                        ------------------------------
                                   Title: Member
                                         -----------------------------

                                   Address: 40 Meadowbrook Road
                                            Old Greenwich, CT 06870

   [Signature Page to Fourth Amended and Restated Investor Rights Agreement]
<PAGE>

                                   ___________________________________
                                   Shelley Sasahara, an individual

                                   ___________________________________
                                   Michael McFarland, an individual

                                   ___________________________________
                                   Terry Painter, an individual

                                   ___________________________________
                                   Tyler Painter, an individual

                                   ___________________________________
                                   Avi Steinlauf, an individual

                                   ___________________________________
                                   Lev Stark, an individual

                                   ___________________________________
                                   Gina Bell, an individual

                                   ___________________________________
                                   Siran Agadjanian, an individual

   [Signature Page to Fourth Amended and Restated Investor Rights Agreement]
<PAGE>

                                   ___________________________________
                                   Michael Boehm, an individual


                                   ___________________________________
                                   Ari Wasserman, an individual


                                   ___________________________________
                                   Kirk Uhler, an individual


                                   ___________________________________
                                   Todd Lindstrom, an individual


                                   ___________________________________
                                   Joe LaRosa, an individual


                                   ___________________________________
                                   Kevin Goldberg, an individual


                                   ___________________________________
                                   Larry Tchamkertenian, an individual

   [Signature Page to Fourth Amended and Restated Investor Rights Agreement]
<PAGE>

                                   ____________________________________
                                   Chris Gaebler, an individual


                                   ____________________________________
                                   Scott Hannah, an individual


                                   ____________________________________
                                   Serko Ashikian, an individual


                                   ____________________________________
                                   Robert Tchamkertenian, an individual


                                   ____________________________________
                                   Chris Camillo, an individual


                                   ____________________________________
                                   Jeffrey Jack, an individual


                                   ____________________________________
                                   Rick Rosenweig, an individual


   [Signature Page to Fourth Amended and Restated Investor Rights Agreement]
<PAGE>

                                   ____________________________________
                                   Daniel Alexander, an individual


                                   ____________________________________
                                   Yvette Clark, an individual

   [Signature Page to Fourth Amended and Restated Investor Rights Agreement]
<PAGE>

                                   SERIES D PURCHASER


                                   ______________________________________
                                   Print Name of Signatory as it is
                                   to appear on stock certificate


                                   ______________________________________
                                   Authorized Signature


                                   ______________________________________
                                   Title of Signatory (if appropriate)


                                   Address:

                                   ______________________________________

                                   ______________________________________

                                   ______________________________________


   [Signature Page to Fourth Amended and Restated Investor Rights Agreement]