Yup, from the rules:
"A user can have a maximum of two accounts. Alternative accounts cannot be used while the main is banned, and vice-versa. Should one account be used while the other is banned, both accounts will be banned for an additional month. Do not take this rule lightly. Alternative accounts are confirmed through IP address. We understand that multiple users may have the same IP address. but there is no other way to confirm whether a user is using multiple accounts other than through an IP address (or e-mail, which is easily changed).
Creating third, fourth, etc accounts will result in the new accounts being permanently banned."