There's a phenomenon here at DKos that I find troubling: Purity Police (PP) Lynchmobs. The PP are groups of people who feel passionately about a current issue, to the extent that they cannot tolerate any disagreement. A Lynchmob occurs when PP gang up on a diary that differs with the popular meme on their issue. They make personal insults to the diarist, giving troll ratings to shut him up by hiding his comments.
Purity Police are often TU's. They in effect "game the system", by hanging out in Lynchmob and clusterfuck diaries where they heap mojo on one another. They also seem to have a lot of free time to spend blogging.