Rumors of a Facebook smartphone have been as persistent as they have been fruitless. But, despite furious predictions to the contrary, the company has yet to launch any hardware. However, the recent revelation of a patent application made by the social network suggests all the talk hasn't been baseless. According to Patent Bolt, Facebook filed for a patent in 2011 covering a that would feature side and/or rear touch inputs in addition to the traditional touchscreen display on the front.

While this doesn't mean you can expect to get your hands on a Facebook-built device any time soon, it's confirmation that Facebook has, in fact, been working on hardware development.[via The New York Times]