http://bits.blogs.nytimes.com/2009/12/02/yahoo-deepens-friendship-with-facebook/?ref=technology
In this article by Brad Stone he talks about the deepened partnership between Face book and yahoo. Beginning some time in the first half of 2010 they will start crossing their streams which is the flow of real-time updates from a person’s sphere of online contacts. There is really no money involved but it is a strategic move designed give each company a broader reach of users.