Through painful experience, we've discovered that some changes to personal profiles will temporarily deactivate accounts. When this happens, admin has to go back in and reactivate the account. It doesn't hurt anything, and don't ask me why it happens, but it does.
So far, changing your e-mail address will deactivate your account. I'm not sure about any other specific changes.
If you are going to go in and change anything, PM either me or Jason to let us know. That way, if we don't hear from you in a day or two, we can go in and make sure you're still active. That will prevent you from actually having multiple accounts (that I still don't know how to merge, if they can actually be merged!)