A list of Facebook's open-sourced applications and their major contributions to other open-source projects can be found here: http://developers.facebook.com/opensource/
"Please take a look, tell us what we did wrong and join us in working together to make every data center more efficient."
Mad Props.
Indeed. This is how I want to see society. Sharing knowledge for the greater good. Probably the reason I'm not a fan of detriments of this such as software patents and Apple in general.