Contrary to popular opinion, on the internet, everyone is what they want to be. Some people are the same, some are not. Some act normally, some act up, some just act a part.
I might be like Cyrano, with all the talkin' and sophisticatedness that I hold back in person. He had the nose. I've got other unusually large parts.
I'm not saying people take on roles, although there are a few... I'm saying that with the likelyhood of never meeting the people at the other "end," you can just be yourself. More likely, be the self you wish you had the guts to be.
I think this effects the shy and bashful more than the loud and obnoxious. Loud Guy may think he should tone it down, but with nothing to stop him, he's just as likely to be "loud" on the internet as in real life.
I, on the otherhand, can talk to anyone I want. It's easy. The opposite of me.
It was once suggested that I go to a blackberry party. Each table has a big number posted and a blackberry. It lets you "chat" from table to table. I can't imagine a more horrible experience. Who can this concept be for? Not the shy people, that's for sure. And, Loud Guy doesn't need a blackberry, does he?