The email server is down just now for a day or two it means you won't get topic notifications (You might get SMTP errors trying to post a message because of this, just ignore it)
And, you won't be able to register because you need to get your account activated via e-mail, accounts that are currently still to be validated while the server is down will be validated by me after e-mail is working again!
I don't think you can private message or e-mail via the forums either while the server is down, but I'd rather keep the forum live for simple purposes...