In person, I try to be civilized, but most of the people I deal with try to remain civilized too, so there you go. Online, it depends on the day - sometimes I get called a name and my reaction is simply a polite form of "bitch please" and don't retaliate in kind; other days, some idiot says something inflammatory and, well, I reply in kind.

Actually, I kind of think of FS and Fandom Wank (and a lot of other online places) as a way for people to vent the things they can't say IRL, or just generally vent. 3/4 of the things shouldn't be taken personally or replied to, probably, but they are. Ah well, life is such.