Facebook has been sued by a software company in the US that claims the social-networking site is violating a two-year-old patent.
Baltimore-based WhoGlue's patent covers an "information management system, method and computer program code and means for facilitating communications between user members of an online network", according to the patent description.
WhoGlue's filings are vague on exactly how Facebook might violate the patent, but it appears to have an issue with the privacy controls Facebook has instituted over the past two years to give its users greater control over who sees what on the social-networking site.
"Recently, the big social networking sites have begun to realise that it's not just about making it easy to share information ... it's also about making it easy to control access to that information," company CEO Jason Hardebeck wrote in a July 11 blog posting.
"We figured that out a long time ago; as a matter of fact, we filed for a patent called 'Distributed personal relationship information management system and methods' (remember, this was before 'social networking' came into vogue) way back in 2001."
The company is asking the court to award damages and attorney fees and to stop Facebook from further infringement.
Founded in 2001, WhoGlue sells web-based relationship management software used by groups such as alumni organizations. The patent in question was issued in July 2007, according to the US Patent and Trademark Office.
Technology giant Siemens holds a 33 percent stake in WhoGlue, according to a 2008 list of the company's subsidiaries.
WhoGlue's Hardebeck declined to comment on the case, saying via e-mail that "at this time we aren't making any public comments".
Facebook representatives did not return messages seeking comment.