I read DU a lot last year but at some point I asked myself "why?"
Life is too short to do more than browse that cesspool.
Now, DUFU is different.
At this time I would like to add a new one. Never respond to any calling out as a FReeper troll. It only gives them another chance to question you.
I don't dive as deep as PJ does, but lighting a lamp of reason in the moral & intellectual darkness that is DU gives me a certain satisfaction and the hope that I can eventually crack the stubborn ignorance of one or two of them. Also, I like getting their goats.