Facebook is accused of using 10 patents belonging to Yahoo! without a proper licence to do so, including inventions related to "measures and systems" for internet advertising, according to a report by news agency Reuters.
"Only two of the 10 patents at issue are directly related to social networking technology. Most focus on online advertising, including methods for preventing 'click fraud,' as well as privacy and technology for customizing the information users see on a Web page," according to Reuters.
Last month a report in the New York Times suggested that Yahoo! was unhappy about Facebook's use of patents relating to online advertising as well as "personalization of Web sites, social networking and messaging". The two companies had been discussing a potential licensing agreement for the patents, but Yahoo! has now submitted its claims with a court in California and claims that an agreement has still to be reached.
"Unfortunately, the matter with Facebook remains unresolved and we are compelled to seek redress in federal court," the company said in a statement, according to the Reuters report.
Facebook said it was "disappointed" with the decision to take legal action by its "longtime business partner". It said Yahoo! has "substantially benefited from its association with Facebook," according to the news agency.
In the lawsuit Yahoo! claims that Facebook's founder has already admitted that "the design of Facebook is not novel and is based on the ideas of others". The site was previously "one of the worst performing sites for advertising" prior to using Yahoo!-patented inventions, it said.