Might be able to use something like this as a starting point (though it's vote-based, but seems to support decay over time) http://code.google.com/appengine/art

Might be able to use something like this as a starting point (though it's vote-based, but seems to support decay over time) http://code.google.com/appengine/articles/overheard.html http://code.google.com/appengine/articles/overheard.html