I've only been on FR since February (although I lurked before that) so I'm not sure what sets off the trolls. It would seem to me the frustration level is high today, because:
(1)The 9/11 Commission admitted they were briefed about the intel;
(2)Cindy SHeehan has been outed as a barking moonbat
I'm sure there are other things that are rattling their cages.
The DSM went nowhere, the Rove thing went nowhere, Tom Delay is still there, Roberts will be confirmed and the NARAL folks are outed as liars, and the beat goes on.
I think you nailed it. Sheehan and the 9/11 Commision. And trolls have a lot of time on their hands anyway :)
You forgot one: Bush is STILL President! LOL
Today was the last "Dog Day" and the metero shower is in full bloom tonight. Perhaps that brings the trolls out?