Yahoo has asserted that Facebook's data center and server technology may infringe upon patents owned by Yahoo and companies it has acquired. Yahoo's claims cover technology included in the Open Compute Project, the open source initiative that has published details of many of Facebook's server and data center designs.
Yahoo hasn't filed suit over the data center and server patents, but is already suing Facebook over alleged infringements on patents related to advertising, social networking, privacy and messaging.
In an April 23 letter to Facebook, Yahoo says that public descriptions of Facebook's designs are "relevant" to proprietary Yahoo technology in 16 patents, including some dating back to 2001. Many of the patents relate to web caching, load balancing and content replication technology developed by Inktomi and WebSpective, two companies acquired by Yahoo.
Other patents cited by Yahoo are more recent and related to cold aisle containment systems developed by Yahoo to isolate airflow and cool servers efficiently.
"We also understand that at least one former Yahoo employee who had responsibility in connection with Yahoo's data centers now has responsibility over the operations of Facebook's data centers," Yahoo wrote.
It's hard to tell whether this is a serious technology beef or posturing ahead of Facebook's IPO, which is scheduled for May 18. Companies preparing to go public sometimes seek to settle legal disputes prior to their IPOs to reduce investor concern that a future judgment will affect the share price.
TechCrunch has posted Yahoo's letter at SlideShare.