Account Name - email associated with your game account (can be changed)
Display Name - name everyone sees, in-game and out (can not be changed)
So it's ok to get snotty Mails from people who don't like your posts? in game?
In-game mail included a 'Report' feature. If someone is being rude, use said feature.
It's a move I really think Anet should be capitalizing on - the ability to change the display name. My current is dissuading me from playing the game and causing me to consider restarting on a new account, no matter how long it would take. I just get really irked over it. I don't mind paying for the display name change either! But I just think its a change that needs to happen, because I know several people who made this account when they were younger and have grown weary of their name.