Brian Krausz
Facebook has acquired eye tracking service GazeHawk for the team behind the technology, according to Brian Krausz, co-founder of GazeHawk.

Normally eye tracking technology requires special hardware, but GazeHawk only uses your web cam. Advertisers and others wanting to optimize their websites, can use the technology to see if anything caught your eye.

The technology is mostly used for companies doing case studies. Users opt-in. It's not like Facebook is suddenly going to turn on your camera secretly and start spying on you.

GazeHawk went through Y Combinator in the summer of 2010. However, the lure of working at Facebook made them bag the technology.

GazeHawk's eye tracking technology and patent will remain separate from Facebook, and the GazeHawk team will start at Facebook next week. Terms of the deal weren't disclosed.