My online personality is AvPD too. On chat i usually end up only saying hi and bye. When i'm on Xbox Live and someone talks, i end up being quiet and hoping they're not talking to me, while trying to be as quiet as possible
It were better on chat channels earlier, when i were 15 years younger, and played the online game Planetarion. Had a little break on a 1-2 years, and when i tried again, it were much more different. Usually only talked when i were drunk, or if we were planning attack or defence in a chat channel.
I do however have a druken online personality that's is more social. Sometimes he knows better that other, and chat much rubbish, and also posts much crap on forums or Facebook when he knows better than others. That drunken personality have given me lots of anxiety, when i've suddenly remembered what i posted last night