There used to be a time on the now abonded drop.org site where there was "Gravity" (like karma in slash) with drupal as described on for example http://www.drop.org/node.php?id=98&cid=358. Is this still in drupal? and if so, where to enable it? Or is this something that was lost somewhere between 3 and version 4?

I would like to see it on my sites again.