Yahoo made good on its promise to sue Facebook, and it looks like they weren't kidding. On Monday, they filed a complaint that Facebook had violated 10 patents.

They make a case that Yahoo innovated on several fronts, including messaging, news feed generation, social commenting advertising display, preventing click fraud and privacy controls.

“Facebook was not launched until 2004, 10 years after Yahoo was founded,” the complaint reads. “Facebook has since grown to be one of the most widely trafficked sites on the Internet. That growth, however, has been based in a large part on Facebook’s use of Yahoo’s patented technology.”

They also quote Facebook CEO Mark Zuckerberg as acknowledging that "getting there first is not what its all about". It goes on to say,  “Facebook’s entire social network model, which allows users to create profiles for and connect with, among other things, persons and businesses, is based on Yahoo’s patented social networking technology.”

Yahoo is seeking some unspecified damages and funnily enough, its at a time when Facebook is going to launch their IPO. They are expected to launch an IPO in May to raise $5 billion.

The suit comes after Yahoo and Facebook were apparently unable to work out an agreement over the issue. Yahoo was in talks with Facebook over its patent claims last month, according to a report in The New York Times.

Complaint for Patent Infringement