Having come from an RP background (pen & paper games to begin with, plus always playing MMOs on RP servers), this is quite a psychological shift. I'm used to having an out of character (OOC) channel for the guilds I've been in, with guild chat being in character (IC). This arrangement may seem strange to those who don't take much notice of the "RP" part of MMORPG, but it's something I'm familiar with and I find to helps reinforce my sense of my character being a separate person from me, which is part of the reason why I play these games. For a roleplayer, it's obvious that my rude, scheming warlock (or my nice but slightly dull druid) aren't me, any more than Robert De Niro is Travis Bickle. For people who aren't from that background, the avatar is the person: if you're rude IC it means you're rude in real life (IRL). Right now, I'm going with a relatively likeable character to avoid potential misunderstandings.
The second strand of this is the level of surprise from my new guildmates as to how nice & helpful people are on Argent Dawn (EU). They seem genuinely amazed that people stop to help them if they look lost, rather than insulting them for being n00bs. To me, this is normal - it's how MMORPGs are played; they are, by nature, highly social games. I've never "got" the frequent accusation that the WOW community is unpleasant, because that hasn't been my experience. With hindsight, the evidence was there for me to see in the cross-server dungeon finder groups I've been in. People rarely spoke except to blame others for their own mistakes or say "gogogo". Whilst this sort of thing is not unknown on RP servers, it is much rarer, and most groups are friendly and helpful to people who are new to a role. It all makes me very glad that AD was chosen as the host server for SAN. I'm not sure I'd have coped anywhere else.
Finally, I'd like to thank all of the Alliance guys who were RP-defending Northwatch Hold using /duel last night. Yes, it interfered with my minor levelling quest, but it made me feel like I was in a real world, where people cared about their faction and castles are more than just places to kill pixels and gain XP.