Ruby

IBM Internet Technology Group chose Drupal over Typo3, Movable Type, and Mambo
First part of their "Using open source software to design, develop, and deploy a collaborative Web site" series. (Typo in one of the graphics.)
Anil Dash lists the items of a truly Web 2.0 service
Which is funny, not least because TypePad only really has the REST API on his mock checklist (in fairness, LiveJournal, with tags and Ajax, comes closer).
Vancouver Ruby News
Uses Drupal, a PHP CMS.