[MagicalTux]

Accounts with special characters will be problematic for the hosting (for example, a vhost !Wan.vip.graal.net isn't really allowed in dns protocol, even if it may work for some people).
I don't know for the three letters limitation, but dots (for example) are forbidden. If dots were working, the GraalHosting would have problems to handle it.

Another reason : when people can make that short accounts, they can try to get the shortest account possible and people will start fighting to get the shortest account names... just look how much someone can sell a 6-digit ICQ number... we don't want that kind of fights on graal, so 3 letters account are not allowed.

MagicalTux