Rails
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).
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