The vBulletin Admin control panel does not provide any means to read the contents of any users' private messages. It does provide functionality in reporting private message statistics (number of users who have 1 private message, have 2 messages, etc. and can list those users). There are also options to delete all of a user's private messages, but I imagine such a function would only be used to save disk space or if they were purging inactive users etc. That said, though, the messages are saved in the board database on the server, so in theory, they could be viewed by an administrator who really wanted to see them (how easily, I don't know). Then again, your e-mail is stored on a server somewhere on the internet and is that any more or any less secure/private? If you truly want private, use encryption.

FewMiles..