The post that was quoted here has been removed
They are immature cretins, but they play everywhere.
I've seen plenty at FICS, US Chess Live, and playchess, too. However, as I recall, they were a bit worse at ICC. I've heard that they make up the vast majority at sites like Yahoo.
My last year or two at ICC (2001-2003), I played in the 5 0 pool almost exclusively. Rematches were never an issue, nor was lag, and verbal abuse was less frequent.
The verbal abuse that has been hardest to forget was when an ambitious FM took issue with me having the gall to comment on a game during the Kramnik-Kasparov WCC match: "I'm an FM, and I have no idea what is going on in this game, how can a mere 1500 have anything to say." He spent the next 15 minutes sending me private tells telling me how stupid I was, while all I said in reply was he should know who he is talking to before rendering such judgements.