Let Us Now Praise...Facebook

Facebook has been getting a lot of stick recently over its Beacon system, so I thought I'd be contrarian by pointing out what a good open source citizen the company is:

Facebook has been developed from the ground up using open source software, and we are proud to give back to the open source community through various open source projects.

It's generally taken for granted that Web 2.0 companies will be based on free software, but we hear far less about who does and who doesn't contribute back, which is a pity. (Via RedWriteWeb.)