system: You are a contract-analysis assistant performing a span-extraction task. You are given an excerpt from a commercial contract and the name of a clause type to locate within it.

Return the exact text of the requested clause, copied verbatim from the excerpt — identical wording and punctuation, with no paraphrasing, summarising, explanation, or added commentary.

The excerpt is one window of a much longer contract and often will not contain the requested clause. If the requested clause does not appear in this excerpt, respond with exactly: Not found.

Output only the extracted clause text, or the exact string `Not found.` — nothing else.

user: Contract excerpt:
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Archived Content to any PaperExchange Competitor. 4. ADVERTISING 4.1. Advertisements on the PaperExchange Site. 4.1.1. During the Term, VerticalNet shall have the exclusive right to arrange for the sale of ***** of the third party advertising inventory (which shall consist of a minimum of one advertisement per page on each of the "Co-Branded Equipment," "Co-Branded Careers," "Resources" and "Home Page" sections or successor, replacement or substitute sections) of the PaperExchange Site and shall be consistent with the amount of advertising on other business to business vertical sites on the PaperExchange Site (the "Third Party Advertising Allocation"). PaperExchange shall retain the right to place advertisements for its own account on the remaining ***** of the Third Party Advertising Allocation; provided, however, that if any portion of such Third Party Advertising Allocation remains unsold 45 days after it becomes available for advertising, VerticalNet shall have the exclusive right to arrange for third party advertising on such unsold Third Party Advertising Allocation. 4.1.2. VerticalNet will use reasonable efforts to sell advertisements on the PaperExchange Site. The advertising policies (including rates and procedures) applicable to VerticalNet's sale of advertising for the PaperExchange Site will be mutually agreed upon by VerticalNet and PaperExchange (the "PaperExchange Advertising Policies"). Any changes to the agreed upon PaperExchange Advertising Policies shall be mutually agreed upon by the parties. * Confidential Treatment Requested: material has been omitted and filed separately with the Commission. 6 4.1.3. VerticalNet shall provide notice to the Director of Online Marketing of PaperExchange of each advertiser that agrees to place an advertisement on a PaperExchange Site on the terms and conditions contained in the then current PaperExchange Advertising Policies. PaperExchange shall then have three business days after receipt of such notice to (a) accept or reject such advertiser, in its reasonable business discretion, and (b) notify VerticalNet of its decision. If, at the end of such three-day period, PaperExchange has not responded to such notice, PaperExchange shall be deemed to have accepted such advertiser. PaperExchange shall then work with the advertiser to facilitate the Placement of the advertisement and maintain such advertisement on the agreed-upon page of the PaperExchange Site. PaperExchange shall have the right to terminate its agreement with any such advertiser in its reasonable business discretion. To the extent an advertisement of equivalent size and location appears on both Pulp and Paper Online and the PaperExchange Site, the parties shall mutually agree upon the CPM, CPC or other use-based advertising rates, which rate shall be identical for such advertisements. PaperExchange shall be responsible for, and shall have sole control of, all credit, billing and collection with the advertisements on the PaperExchange Site. VerticalNet shall have no authority to make collections on behalf of PaperExchange. Source: PAPEREXCHANGE COM INC, S-1/A, 3/22/2000 4.2. Sales Leads. PaperExchange will, in its sole discretion, request that its Board of Directors and veteran industry sales force use reasonable efforts to provide pulp and paper industry specific sales strategies and specific sales leads to VerticalNet. Such strategies and leads shall include segments of the industry that are currently lacking effective advertising solutions, and how such industry participants could be marketed to by VerticalNet for the purposes of this Section 4. VerticalNet may only use the information provided to them pursuant to this Section 4.2 [Sales Leads] in connection with its performance under this Section 4. 4.3. Non-Competition. 4.3.1. During the Term, VerticalNet shall not (a) act as an advertising agent or representative for any PaperExchange Competitor and (b) place any advertisements on Pulp and Paper Online from any PaperExchange Competitor. 4.3.2. During the Term, PaperExchange shall not place any advertisements on the PaperExchange Site from any Pulp and Paper Online Competitor. 5. CO-MARKETING ACTIVITIES 5.1. Trade Shows and Conventions. 5.1.1. During the Term, PaperExchange shall use commercially reasonable efforts to expand its presence at major national and international pulp and paper industry trade shows and conventions, including booth exhibitions, attendance by industry veteran sales force from all the major paper grades and industry panel sponsorships, when available. PaperExchange, in its reasonable business discretion, shall actively engage in co-branded activities with VerticalNet at PaperExchange's booth exhibitions and shall maintain an open invitation policy for VerticalNet to send its own sales force to co-locate, subject to Section 5.1.3 [Trade Shows and Conventions], with PaperExchange at its trade show booths. 5.1.2. VerticalNet, in its reasonable business discretion, shall offer PaperExchange 7 exhibit booth space at pulp and paper industry trade shows that VerticalNet is unable to use on the same terms that VerticalNet accepted
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Extract the exact clause related to "Parties" from the excerpt above.