You may have noticed that there is sometimes a discrepancy between the Who's Online page and the list of Online Users on the left.

This happens when a user who has been online leaves their browser window open and goes off to do somethine else. In other words, they are signed in, but get distracted, or just walk away from the computer without logging out.

After 30 mins their session times out, but the Online Users list will still show them as still online because the little piece of software is still running on the page they were on before they abandoned it to do something else.