I just want to remind people of these two options. I've been trying (and failing) to get an urgent message to two people, and assume they have not checked these two boxes.The forum can send a message to your email address to inform you when someone sends you a private message.
Receive Email Notification of New Private Messages
If you are browsing the forums when you receive a new private message, the system can pop-up a notification box informing you of the new message.
Show New Private Message Notification Pop-up
Go to Your Account, (green line at the top), click Edit Options (on the lefy), scroll down to PM options and check these two boxes. You can actually read the PM in your email inbox, so you know if it's urgent.
Particularly useful if you don't use PMs much, so don't check regularly.