Mumbai: Creating a sensation in electronic social media circles, Yahoo has sued Facebook over 10 patents that include methods and systems for advertising on the Web.

The lawsuit was filed in a San Jose, California Federal Court, on Monday and marked a major escalation of patent litigation that has already swept up the smartphone and tablet sectors and high-tech stalwarts such as Apple Inc, Microsoft Corp and Motorola Mobility
Holdings Inc.

The lawsuit comes on the heels of Facebook?s announcement of plans for an initial public offering that could value the company at about $100 billion.

According to Reuters report, Facebook spokesman Jonathan Thaw said Facebook learned of the lawsuit through the media. The report quoted him as saying: "We are 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.?

In reply, Yahoo said in an emailed statement that it is confident it will prevail. The statement quoted by Reuters said, "Unfortunately, the matter with Facebook remains unresolved and we are compelled to seek redress in federal court.?

It was reported that Yahoo was seeking licensing fees from Facebook over its patents and that other companies have already agreed to such licensing deals. Two of the 10 patents at issue are directly related to social networking technology. Most of these 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.

A classic defense for companies targeted with patent claims is to threaten a countersuit using its own patents. But in this case Yahoo possesses far more patents than Facebook. According to a US government database, Yahoo has over 3,300 patents and published patent applications while in comparison Facebook has a mere 160.