In large part, however, Yahoo was looking for a way to put the lawsuit behind it, said Karsten Weide, an analyst with IDC. "Primarily, I think this is Yahoo saying, 'Oops, sorry we bothered you with the patent stuff.' We're going to go home now," he said.

But in the process, Yahoo secured a piece of the social pie that Facebook dominates. "Yahoo can go to [advertising] customers and say, look, you wanted social and we've got social," he said.

On Facebook's side, it will likely benefit from the access it gains to some of Yahoo's content.

"One of the real opportunities [for Facebook] moving forward is using their platform to distribute content," said Allen Weiner, a Gartner analyst.

"Facebook wants to beef up their supply of content that can be shared across the Facebook network. They don't really have any of their own content, be it original or even aggregated, so Yahoo makes a logical partner for that," Weiner said.