<PAGE>
                                                                     EXHIBIT 4.5


                             REGISTRATION AGREEMENT


               THIS REGISTRATION RIGHTS AGREEMENT (this "Agreement") is made as
of May ____, 2001, between L90, Inc., a Delaware corporation (the "Company") and
Novus List Marketing, LLC, a Minnesota limited liability company ("Investor").

               The parties to this Agreement are parties to that certain Asset
Purchase Agreement, dated of even date herewith (the "Purchase Agreement") among
the Company, Investor and Henry A. Cousineau III. In order to induce Investor to
enter into the Purchase Agreement, the Company has agreed to provide the
registration rights set forth in this Agreement. The execution and delivery of
this Agreement is a condition to the Closing under the Purchase Agreement.
Unless otherwise provided in this Agreement, capitalized terms used herein shall
have the meanings set forth in paragraph 5 hereof.

               The parties hereto agree as follows:

               1.  Demand Registration.

               (a) Request for Registration. Subject to the other provisions
herein, at any time after the six (6) month period following the Closing Date,
the holders of at least a majority of the Registrable Securities may request
registration under the Securities Act of all or any portion of their Registrable
Securities on Form S-3 provided that Company is eligible to register securities
on Form S-3 under the Securities Act or on Form S-1 in the event that the
Company is not eligible to register securities on Form S-3 under the Securities
Act (a "Short-Form Registration"). The holders of Registrable Securities shall
be entitled to request one (1) Short-Form Registration for which the Company
shall pay all Registration Expenses (as defined in Section 3 hereof) up to
$10,000; provided, however, that the aggregate offering value of the Registrable
Securities requested to be registered in such Short-Form Registration must equal
at least $1,000,000 or must constitute all of the Registrable Securities. The
request for a Short-Form Registration shall be in writing and specify the
approximate number of Registrable Securities requested to be registered and the
anticipated per share price range for such offering. Within ten days after
receipt of any such request, the Company shall give written notice of such
requested registration to all other holders of Registrable Securities and shall
include in such registration all Registrable Securities with respect to which
the Company has received written requests for inclusion therein within 15 days
after the receipt of the Company's notice. Company shall cause such Short-Form
Registration to be declared effective by the Securities and Exchange Commission
no later than the six (6) month anniversary of the date of this Agreement.

                (b) Lock-Up. As a condition to registering the Registrable
Securities of any holder thereof, such holder shall, upon submitting a request
for registration pursuant to this Agreement, deliver to the Company a duly
executed agreement in substantially the form attached hereto as Exhibit A.



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               2. Registration Procedures. Whenever the holders of Registrable
Securities have requested that any Registrable Securities be registered pursuant
to this Agreement, the Company shall use commercially reasonable efforts to
effect the registration and the sale of such Registrable Securities in
accordance with the intended method of disposition thereof and pursuant thereto
the Company shall as expeditiously as possible:

               (a) prepare and file with the Securities and Exchange Commission
a registration statement on Form S-3 or Form S-1, as applicable, with respect to
such Registrable Securities;

               (b) prepare and file with the Securities and Exchange Commission
such amendments and supplements to such registration statement and the
prospectus used in connection therewith as may be necessary to keep such
registration statement effective for a period of not less than 180 days, and
comply with the provisions of the Securities 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;

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

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

               (e) notify each seller of such Registrable Securities, at any
time when a prospectus relating thereto is required to be delivered under the
Securities Act, of the happening of any event as a result of which the
prospectus included in such registration statement contains an untrue statement
of a material fact or omits any fact necessary to make the statements therein
not misleading, and, at the request of any such seller, the Company shall
prepare a supplement or amendment to such prospectus so that, as thereafter
delivered to the purchasers of such Registrable Securities, such prospectus
shall not contain an untrue statement of a material fact or omit to state any
fact necessary to make the statements therein not misleading;

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



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

               (h) in the event of the issuance of any stop order suspending the
effectiveness of a registration statement, or of any order suspending or
preventing the use of any related prospectus or suspending the qualification of
any common stock included in such registration statement for sale in any
jurisdiction, the Company shall use commercially reasonable efforts promptly to
obtain the withdrawal of such order.

                        3.   Registration Expenses.  Expenses incident to the
Company's performance of, or compliance with, this Agreement, including without
limitation all registration and filing fees, fees and expenses of compliance
with securities or blue sky laws, printing expenses, messenger and delivery
expenses, fees and disbursements of custodians, and fees and disbursements of
counsel for the Company and all independent certified public accountants,
underwriters (excluding discounts and commissions (which shall be borne pro rata
by the holders of Registrable Securities included in such registration) and
excluding fees and disbursements of any counsel retained by any holder of
Registrable Securities included in such registration (which shall be borne by
such holder)) and other Persons retained by the Company (all such expenses being
herein called "Registration Expenses"), shall be borne by the Company up to
$10,000 in the aggregate. Registration Expenses in excess of $10,000 shall be
borne by all sellers of securities included in such registration in proportion
to the aggregate selling price of the securities to be so registered.

               5.     Indemnification.

               (a) The Company agrees to indemnify, to the extent permitted by
law, each holder of Registrable Securities, its officers and directors and each
Person who controls such holder (within the meaning of the Securities Act)
against all losses, claims, damages, liabilities and expenses caused by any
untrue or alleged untrue statement of material fact contained in any
registration statement, prospectus or preliminary prospectus or any amendment
thereof or supplement thereto or any omission or alleged omission of 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, except
insofar as the same are caused by or contained in any information furnished in
writing to the Company by such holder expressly for use therein or by such
holder's failure to deliver a copy of the registration statement or prospectus
or any amendments or supplements thereto after the Company has furnished such
holder with a sufficient number of copies of the same.

               (b) In connection with any registration statement in which a
holder of Registrable Securities is participating, each such holder shall
furnish to the Company in writing such information and affidavits as the Company
reasonably requests for use in connection with any such registration statement
or prospectus and, to the extent permitted by law, shall indemnify the Company,
its directors and officers and each Person who controls the Company (within the


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meaning of the Securities Act) against any losses, claims, damages, liabilities
and expenses resulting from any untrue or alleged untrue statement of material
fact contained in the registration statement, prospectus or preliminary
prospectus or any amendment thereof or supplement thereto or any omission or
alleged omission of 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, but only to the extent that such untrue statement or
omission is contained in any information or affidavit so furnished in writing by
such holder.

               (c) Any Person entitled to indemnification hereunder shall (i)
give prompt written notice to the indemnifying party of any claim with respect
to which it seeks indemnification (provided that the failure to give prompt
notice shall not impair any Person's right to indemnification hereunder to the
extent such failure has not prejudiced the indemnifying party) and (ii) unless
in such indemnified party's reasonable judgment a conflict of interest between
such indemnified and indemnifying parties may exist with respect to such claim,
permit such indemnifying party to assume the defense of such claim with counsel
reasonably satisfactory to the indemnified party. If such defense is assumed,
the indemnifying party shall not be subject to any liability for any settlement
made by the indemnified party without its consent (but such consent shall not be
unreasonably withheld). An indemnifying party who is not entitled to, or elects
not to, assume the defense of a claim shall not be obligated to pay the fees and
expenses of more than one counsel for all parties indemnified by such
indemnifying party with respect to such claim, unless in the reasonable judgment
of any indemnified party a conflict of interest may exist between such
indemnified party and any other of such indemnified parties with respect to such
claim.

               (d) The indemnification provided for under this Agreement shall
remain in full force and effect regardless of any investigation made by or on
behalf of the indemnified party or any officer, director or controlling Person
of such indemnified party and shall survive the transfer of securities.

               6.     Definitions.

               (a) "Registrable Securities" means (i) any Common Stock issued
to Investor pursuant to the Purchase Agreement and (ii) any Common Stock issued
or issuable with respect to the securities referred to in clause (i) above by
way of a stock dividend or stock split or in connection with a combination of
shares, recapitalization, merger, consolidation or other reorganization. As to
any particular Registrable Securities, such securities shall cease to be
Registrable Securities when they have been (i) distributed to the public
pursuant to an offering registered under the Securities Act or (ii) sold in a
transaction exempt from the registration and prospectus delivery requirements of
the Securities Act under Section 4(1) thereof. For purposes of this Agreement, a
Person shall be deemed to be a holder of Registrable Securities, and the
Registrable Securities shall be deemed to be in existence, whenever such Person
has the right to acquire directly or indirectly such Registrable Securities
(upon conversion or exercise or in connection with a transfer of securities or
otherwise, but disregarding any restrictions or limitations upon the exercise of
such right), whether or not such acquisition has actually been


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effected, and such Person shall be entitled to exercise the rights of a holder
of Registrable Securities hereunder.

               (b) "Subsidiary" of a Person means any corporation, partnership,
association or other business entity at least 50% of the outstanding voting
power of which is at the time owned or controlled, directly or indirectly, by
such Person or by one or more of such subsidiary entities, or both.

               (c) "Person" shall mean all natural persons, corporations,
business trusts, associations, companies, partnerships, limited liability
companies, joint ventures and any other entities.

               (d) Other capitalized terms used herein and not otherwise defined
herein shall have the respective meanings assigned to such terms in the Purchase
Agreement.

               6.     Miscellaneous.

               (a) No Inconsistent Agreements. The Company shall not hereafter
enter into any agreement with respect to its securities which is inconsistent
with or violates the rights granted to the holders of Registrable Securities in
this Agreement.

               (b) Remedies. Any Person having rights under any provision of
this Agreement shall be entitled to enforce such rights specifically to recover
damages caused by reason of any breach of any provision of this Agreement and to
exercise all other rights granted by law. The parties hereto agree and
acknowledge that money damages may not be an adequate remedy for any breach of
the provisions of this Agreement and that, in addition to any other rights and
remedies existing in its favor, any party shall be entitled to specific
performance and/or other injunctive relief from any court of law or equity of
competent jurisdiction (without posting any bond or other security) in order to
enforce or prevent violation of the provisions of this Agreement.

               (c) Amendments and Waivers. Except as otherwise provided herein,
the provisions of this Agreement may be amended or waived only upon the prior
written consent of the Company and holders of at least a majority of the
Registrable Securities.

               (d) Successors and Assigns. All covenants and agreements in this
Agreement by or on behalf of any of the parties hereto shall bind and inure to
the benefit of the respective successors and assigns of the parties hereto
whether so expressed or not.

               (e) Transfer of Registration Rights. Provided that the Company
is given written notice by the holder of Registrable Securities at the time of
any transfer of Registrable Securities by such holder stating the name and
address of the transferee of such Registrable Securities and identifying the
securities with respect to which the rights under this Agreement are being
assigned, the rights of a holder of Registrable Securities under this Agreement
may be transferred in whole or in part at any time to any such transferee, so
long as such transfer of


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securities is in accordance with all applicable state and federal securities
laws and regulations and so long as such transferee agrees in writing to become
subject to the provisions of this Agreement as if such transferee was a party
hereto.

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

               (g) Counterparts. This Agreement may be executed simultaneously
in two or more counterparts (including by facsimile), any one of which need not
contain the signatures of more than one party, but all such counterparts taken
together shall constitute one and the same Agreement.

               (h) Descriptive Headings.  The descriptive headings of this
Agreement are inserted for convenience only and do not constitute a part of
this Agreement.

               (i) Governing Law. All issues and questions concerning the
construction, validity, interpretation and enforcement of this Agreement and the
exhibits and schedules hereto shall be governed by, and construed in accordance
with, the laws of the State of New York, without giving effect to any choice of
law or conflict of law rules or provisions (whether of the State of New York or
any other jurisdiction) that would cause the application of the laws of any
jurisdiction other than the State of New York.

               (j) Notices. All notices, demands or other communications to be
given or delivered under or by reason of the provisions of this Agreement shall
be in writing and shall be deemed to have been given when delivered personally
to the recipient, sent to the recipient by reputable overnight courier service
(charges prepaid) or mailed to the recipient by certified or registered mail,
return receipt requested and postage prepaid. Such notices, demands and other
communications shall be sent to the Investor or the Company, as applicable, at
the address indicated below:

                      Company:      L90, Inc.
                                    4499 Glencoe Avenue
                                    Marina del Rey, CA 90292
                                    Attn:  Chief Executive Officer
                                    Telecopy: 310-578-9942

                      Investor:     Novus List Marketing, LLC
                                    Attn. Scott T. Jagodzinski
                                    13605 First Avenue North
                                    Plymouth, Minnesota  55441


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                                    Telecopy: 763-476-7701

                                    with a copy to:

                                    Fafinski Mark & Johnson, P.A.
                                    Attn. Robert R. Fafinski, Jr.
                                    6600 City West Parkway
                                    Suite 300
                                    Eden Prairie, MN 55344
                                    Telecopy: 952-995-9577

                                   *     *     *     *    *



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                         [REGISTRATION RIGHTS AGREEMENT]




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


                                    COMPANY:

                                    L90, INC.


                                    By: _______________________________
                                           Name:
                                           Title:


                                    INVESTOR:

                                    NOVUS LIST MARKETING, LLC


                                    By: _______________________________
                                       Name:
                                       Title:



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                                    EXHIBIT A

                                LOCK-UP AGREEMENT


                                                              ___________, 200__

L90, Inc.
4499 Glencoe Avenue
Marina del Rey, CA 90292


        Re:  Novus List Marketing

Ladies and Gentlemen:

               Pursuant to Section 1(b) of that certain Registration Rights
Agreement (the "Agreement"), dated May ____, 2001, between L90, Inc., a Delaware
corporation ("L90") and Novus List Marketing, LLC ("NLM"), the undersigned
hereby agrees that the undersigned will not, without the prior written consent
of L90, directly or indirectly, offer, sell, assign, transfer, pledge, contract
to sell, or otherwise dispose of fifty percent (50%) of the shares of common
stock, par value $.001, of L90 held by the undersigned registered pursuant to
the terms of the Agreement for a period of ninety (90) days following the
effectiveness of the registration statement pursuant to which such shares are
registered.

               Anything contained herein to the contrary notwithstanding, any
person to whom shares of Common Stock are transferred from the undersigned shall
be bound by the terms of this Agreement.


                                         Very truly yours,


                                         By:________________________
                                         Name:


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