"David Recordon is the Senior Open Programs Manager at Facebook, where he leads open source and open standards initiatives. He joined Facebook from Six Apart where he focused on platform strategies, and previously worked at VeriSign in the emerging business group. David has played a pivotal role in the development and popularization of key social media technologies, such as OpenID and OAuth."
It's pretty high level but the numbers are impressive. Today they are taking in between 80 and 90 TB of data a day. In 2008 they only took in about 1.2 TB. Check it out for a cool insight that isn't focused on the privacy issues they are dealing with but the real nuts and bolts technology and how most of it, if not all of it, is Open Source. On the Facebook Web Site there is even a whole page dedicated to the Open Source they use, support, created and released.