Another example, in my opinion, is the prevalence of threads in the US General Discussion cherry-picking quotes from Tea Party "leaders" (though I dispute that such a decentralized movement doesn't have any true leaders) that reinforce their perceptions that the Tea Party is full of crazy folk. This is (as far as I have seen) tolerated. Last I checked that board the other day (lurking, of course) I found that the top two threads were such anti-Tea Party threads. Similar threads about leftist groups would probably not be tolerated in the same way.
I'm not sure how much anything on the US General Election board can be held as an example of anything in terms of moderation. I was working on political campaigns through election season and too busy to do much on that board, and for administrative reasons, intentionally avoided more than the barest of moderating for the last few weeks (I deleted an nkspam thread and helped silence a Hamilton sock but that's it -- I even denied someone's request to merge two threads who PM'd me.). I probably wouldn't have deleted pornography from the board had any been posted last week.
I'm planning to reengage the board now that I have the internet set up at my apartment.
