&gt; 70% probability is a very conservative filter and will catch about 10% and a little bit less than half of them will actually be damaging.<p>Right. This is really interesting. A while ago I wrote a classifier that predicted based on a number of criteria if a new member of a web community would be trouble or not. It also worked as an aid in classification and not as a stand-alone decision maker. You have a lot more data to work with so that should make the problem a bit more tractable.<p>Does it use other bits of knowledge about the edit prior probability of a revert for an edit by that particular user or network range for instance?