Facebook has been accused of infringing on patents held by a Dutch computer programmer who tried to launch a similar site more than a decade ago.
The social media giant is being sued in the USA by a holding company called Rembrandt Social Media over allegations that a Dutch programmer, Joannes Van Der Meer, filed for patents in 1998, claiming methods for running a web-based personal diary.
According to a lawsuit heard by a federal jury at US District Court in Alexandria, Virginia, the patents were issued in 2001 and 2002, before Facebook debuted in 2003, but Van Der Meer's website, Surfbook, never got off the ground and he died in 2004.
Facebook, based in Menlo Park, California, says the patents should never have been issued to Van Der Meer, arguing that the ideas and methods put forward in Van Der Meer's patents were obvious to people in the trade.
An expert giving evidence for the plaintiff, University of Maryland professor Jennifer Golbeck, said the technical aspect of the infringement centres on a technology used by Facebook called Bigpipe, which speeds the way web pages are loaded.
More generally, Rembrandt says features on Facebook, including the "like" and "share" buttons, as well as adjustable privacy settings were all anticipated under Van Der Meer's patents.
"Although Mark Zuckerberg did not start what became Facebook until 2003, it bears a remarkable resemblance, both in terms of its functionality and technical implementation, to the personal web page diary that Van Der Meer had invented years earlier," Rembrandt's lawyers wrote in their complaint.
Rembrandt, according to its website, is a company that specialises in filing lawsuits on behalf of patent holders. It has been derided by critics as a "patent troll" that tries to extort hefty settlements from successful companies by digging up obscure patents and claiming infringement.
Bu it is unusual for patent-infringement lawsuits to make it all the way to a federal jury trial and the company fought unsuccessfully for more than a year to keep the case from getting to a jury.
Jason Rantanen, a law professor at the University of Iowa who specialises in patent law, said that roughly 1 per cent of the thousands of infringement lawsuits filed every year end up in that group.
Facebook, a frequent target of patent lawsuits, has typically been successful in fending them off. Rantanen said he could find only one other case where Facebook was the primary defendant in a patent-infringement trial that went to a jury and Facebook won that case.
But once a case gets to a jury, though, it becomes unpredictable, Rantanen said, though one factor that may work in Facebook's favour is what is known in patent law as "hindsight bias".
Jurors looking back on the rapidly evolving history of social media and Facebook's ubiquitous status may conclude that the development of websites like Facebook was inevitable and that the ideas in Van Der Meer's patents were not unique.
The plaintiff "has to overcome the tendency to say, 'Hey, it was all going in this direction anyway'", Rantanen said.
Another factor in Facebook's favour is a pre-trial ruling from Judge TS Ellis III that bars Rembrandt's expert on potential damages from giving evidence. As a result, it is unclear what kind of judgment Rembrandt could win if the jury finds that Facebook has infringed. In court papers, though, Facebook has expressed concern that it could still be subject to millions of dollars in damages.
Neither Rembrandt nor Facebook returned calls seeking comment.