Facebook has bought a web-based operating system developer from the co-founders of the Firefox open-source browser project.

Parakey, a California-based startup, has not actually shipped a product, but is in the process of developing technology it says combines the best of the desktop and web-based software world.

In a November 2006 interview Parakey founder Blake Ross described the company's eponymous product as "a web operating system that can do everything an OS can do".

Ross and Parakey's other founder Joe Hewitt will work on Facebook's website as well as the Facebook Platform, a set of application program interfaces (APIs) that developers can use to write applications for the social networking site.

The two entrepreneurs were co-founders of Firefox and formed Parakey in 2006.