Facebook has launched a counterclaim against Yahoo's patent infringement lawsuit, using patents it has only just bought.
Yahoo sued Facebook last month for infringing its patents, claiming: "Facebook's entire social network model … is based on Yahoo!'s patented social networking technology."
Rather than just refuting the claims it appears the social network has gone on the offensive, using recently bought patents to sue Yahoo right back.
Facebook is now alleging infringements of 10 of its patents that cover Flickr, Yahoo's homepage and various other pages from Yahoo's site. The offending items include personalised story feeds, tagging digital media and user recommendation systems among others.
Buying a defence
Some of those patents have only just been acquired by Facebook, suggesting that the company bought them specifically for this case. It's likely some of them could have come from the haul of 750 patents that Facebook bought from IBM last month.
When Yahoo first sued Facebook, it was notable how few patents Facebook owned compared to its competitors, but a buying spree has since bridged that gap.
Facebook has even gone a step further, arguing in its answer to Yahoo's claim that it has "an express and/or implied license under one of (sic) more of the patents-in-suit." In other words, their previous partnerships gave Facebook the right to use some of Yahoo's patents.
This one is sure to roll on for a while.