Developments in Facebook's quest for patents, as Facebook and Yahoo dispute over issue

As Facebook prepares for its initial public offering of stock, it is in a dispute with Yahoo over patents.

Here are some developments related to that:

Feb. 28: Yahoo Inc. confirms that it is threatening to sue Facebook if it doesn’t reach an agreement over patents.

March 12: Yahoo sues Facebook, claiming that Facebook has infringed 10 of its patents covering advertising, privacy controls and social networking. The lawsuit is filed in U.S. District Court in San Jose, Calif. It seeks unspecified damages.

March 22: Facebook confirms it bought patents from IBM Corp. The 750 patents cover technologies that deal with software and networking.

April 3: Facebook files its own lawsuit against Yahoo, accusing the struggling Internet pioneer of violating 10 patents covering photo tagging, advertising, online recommendations and more. The case is filed in U.S. District Court in San Francisco.

April 9: Microsoft announces that it is buying more than 800 patents from AOL Inc. in an auction and licensing others from AOL for $1 billion.

Monday: Microsoft and Facebook announce that Microsoft is selling about 650 AOL patents and patent applications to Facebook for $550 million. They also agree to a cross-licensing arrangement for the AOL patents they now own.