Yahoo files lawsuit against Facebook Yahoo is suing Facebook over 10 patents that include methods and systems for advertising on the Web. Photograph: Justin Sullivan/Getty Yahoo is suing Facebook over 10 patents that include methods and systems for advertising on the Web, according to a copy of the lawsuit. The lawsuit, filed in a San Jose, California federal court, marks the first major legal battle among technology giants in social media and a major escalation of patent litigation that has already swept up the smartphone and tablet sectors and high-tech stalwarts such as Apple, Microsoft and Motorola. Yahoo's patent lawsuit follows Facebook's announcement of plans for an initial public offering that could value the company at about $100 billion. In an emailed statement, Yahoo said it is confident it will prevail. "Unfortunately, the matter with Facebook remains unresolved and we are compelled to seek redress in federal court," the company said. Several social networking companies, including Facebook, have seen an upsurge in patent claims asserted against them as they move through the IPO process. However, most of those lawsuits have been filed by patent aggregators that buy up intellectual property to squeeze value from it via licensing deals and none by a large tech company such as Yahoo.