|When you log in, you set a cookie on your computer so that you can browse the forums without having to enter your username and password each time. Logging out clears that cookie to ensure nobody else can browse the forum using your ID.
To log in, simply click the login link at the top right hand corner of the forum. To log out, click the log out link in the same place. In the event you cannot log out, clearing cookies on your computer will have the same effect.