This would be most useful if they're maintained per-category, by the people who frequent those categories. So then each filter list has "moderators" who can add stuff to it, the people who frequent a category usually subscribe to its most popular filter list, but nobody is required to.
Then because it's community-moderated and non-centralized you don't get the same problems with you do with email spam filtering where people will try to get their competitors' non-spam senders added to the global spam filter list.