More than a year ago I wrote about the online discourse, which has been instructive for me overall but, as I observe, is distracting if not destructive in some quarters. The people who spray venom more than they bring constructive energy do little to advance anyone's cause, and I call some of they keyboard cowards (they say things with a keyboard they would never say face-to-face).
Via Doc Searls this morning, here's an instructive (and scary) article from Line 56 about what's wrong with blogs. Are blogs, in fact, cults? I don't think so, but will allow that the online world shares many cultish traits -- you can't deny there's elitism, turf battles, conceit, and general exachange of gunfire (including flat-out unprovoked and destructive grenade-throwing).
It's not all like that, of course. I had a discussion an hour ago recounting how much I've learned from others by doing this -- in fact it's the primary reason I do. You can probably safely say that the behavior you observe online mirrors what you observe driving in traffic, going to the supermarket, watching a ballgame, or anything else from the daily rote of life -- some contribute and are overall constructive, but some are selfish and overall destructive.
If you're looking at blogs as a PR outlet, yet more reason to do your homework and have your act together before you get started. Once the shell fire starts, it's more than a full-time job to keep up.