I'll address this anyway, I can guess what you were querying, it's the second today.
Passwords are set to expire after 720 days,
this weeds out inactive accounts. (We poor staffers have to change ours much more frequently).
This is going to come up a lot in the next few days because of the number of people who had to register for the new vbulletin boards after the crash of the ubb boards back in early 2008.
If anyone meets with any problems with this please email me at
[email protected]. It's not unknown for the re-activation email to be dumped in spam and lost.