When I have etiquette dilemmas, I go to Marna, because she is SMRT.  Here’s a post of hers about Reasons to be nice to people in online fandom.

14) One of the many ways in which fandom is not like high school is that fandom is full of extremely smart people. We are not short of clever around here. The bar for “So smart you will automatically be loved and admired, even if you behave like a wild squirrel brought indoors” is set much, much higher than you think it is, and you are probably in no danger of concussing yourself on it.

She’s talking about “online fandom” mostly in the context of media fandom as it is done on LiveJournal, I think, but she’s active in other streams of SF fandom and you can bet she’s seen every one of these points play out on mailing lists or at cons or wherever.  Listen to Auntie Marna.