The new vBulletin software has the ability to be customized to suit your individaul needs. Go to the <User CP> on the left end of the Toolbar and click. Down the left side of the screen you will find the various options for setting passwords, Avatars, and a host of other features including email notification, messaging and so on.
It will not hurt to go in and change the settings and try them out. You can always go back and change them again.