Logoff
The Logoff function saves some of your session data to disk and frees server memory associated with your session. Closing your browser window or moving to a different web site without logging off consumes a small amount of server memory until the inactive session timeout is reached after one hour.
However, as long as your browser remains open it will retain a session cookie with data that matches the session data written to disk. If you return to the DigitalRockArt web site, you will be logged on automatically. This presents a security issue if you access DigitalRockArt from a public server -- closing all running copies of the browser will delete the session cookie and prevent the next user of the public computer from misuse of your ID.