Yahoo has decided to sue Facebook over patent infringement, filing a 19-page lawsuit in San Jose federal court today.

The suit concerns 10 patents Yahoo holds related to advertising, privacy, customization, messaging and social networking. Last week Yahoo threatened to take legal action against the social network unless it began paying Yahoo licensing fees. The lawsuit could negatively affect Facebook’s initial public offering expected later this spring.

In light of the suit, Facebook released the following statement:

We’re disappointed that Yahoo, a longtime business partner of Facebook and a company that has substantially benefited from its association with Facebook, has decided to resort to litigation. Once again, we learned of Yahoo’s decision simultaneously with the media. We will defend ourselves vigorously against these puzzling actions.

Yahoo is asking for Facebook to be permanently prevented from any further infringement of Yahoo’s patents, for Facebook to be ordered to pay Yahoo triple damages due to the “willful and deliberate nature of the infringement” and for both pre- and post-judgement interest on damages. Yahoo is also asking for Facebook to pay all legal costs associated with the court case.

According to AllThingsD, Yahoo’s new CEO Scott Thompson is behind the aggressive move as he seeks to turn the company’s flagging fortunes around. Many industry watchers are puzzled over the move, considering the benefit Yahoo has seen from integrating Facebook’s Open Graph — just three weeks ago Facebook used Yahoo as an example of a success story on its mobile platform. Yahoo took similar, albeit less potentially damaging actions against Google before its IPO in 2004.

The full legal filing is below:

Complaint