What they post seems to be attempts to stir up dissent, and sometimes they are successful, but usually, they prove to be the idiots they are. the tactics are the same Rovian ways: posts built on half truths, assumptions, inflammatory words, and attacks. Usually, we let them post & rant while we rebut their arguments, but their seems to more of them putting up diaries now. I think some trolls are postings under different names, too and (I don't know the slang for it) ganging up on a topic.
I think this is a planned attack to try to destroy or discredit the Dkos community. The Repugs have seen how effective we are in getting good honest into office who really care about their fellow Americans, and they want to stop that. Since money, lies, smears, hate & bribes wouldn't do it, a stealth is all they have to go on.