You could implement this as a service on top of couchdb. The oreilly couchdb book that has just been released shows examples of developing apps using the javasc

You could implement this as a service on top of couchdb. The oreilly couchdb book that has just been released shows examples of developing apps using the javascript engine that's inside couchdb. You'd get easy access to some functionality by doing this - tagging, email versioning.