Facebook Files Patent Countersuit Against Yahoo
 

Sue me will ya? Oh yeah? Oh yeah? Well I am going to sue you right back! How do you like me now? Facebook's lawsuit Tuesday comes just weeks after Yahoo claimed that Facebook violated 10 patents covering advertising, privacy controls and social networking. Facebook denies Yahoo's allegation and now claims that Yahoo violated 10 of its patents covering photo tagging, advertising, online recommendations and more. Facebook says it has been "irreparably harmed" by Yahoo's infringement.

http://www.hardocp.com/news/2012/04/...against_yahoo/