I've been a moderator/host/forum leader for various bulletin boards and other online communities since the early 1980s; first on CompuServe, later on GEnie and AOL, and then professionally in the early days of Consensus Development. One of the behaviors that happens in online communities and that I rarely see elsewhere is flaming -- where one member writes an extremely inappropriate, typically passionately worded attack on another. Flaming behavior can hurt an online community.

ExtrapolateTo infer an unknown from something that is known; conjecture.-- The Random House College Dictionary Mick LaSalle, an acerbic movie reviewer for the San Francisco Chronicle, writes a regular column "Ask Mick LaSalle" in the Sunday paper, where he sometimes allows others to vent their displeasure at his movie reviews. In this week's column he says something that I find very accurate to my experience with the online medium: As for why people get hostile when they hear a differing opinion, I go back to Spinoza's definition of love and hatred.