Yahoo! and Facebook today announced that they have entered into definitive agreements that launch a new advertising partnership, extend and expand distribution arrangements, and settle all pending patent claims between the companies.

Under the agreements, which include a patent portfolio cross-license, the parties will work together to bring consumers and advertisers premium media experiences promoted and distributed across both Yahoo! and Facebook. Yahoo! and Facebook will also work together to bring Yahoo!’s large media event coverage to Facebook users by collaborating on social integrations on the Yahoo! site.

via newsroom.fb.com

It's one of those scratching backs deal, no exchange of money in this case.