There are three options this board can use to detect inactivity and mark threads as read:
1) Inactivity/Cookie Based - once a user has been inactive for a certain amount of time (the value of the cookie timeout option) all threads and forums are considered read. Individual threads are marked as read within a session via cookies. This option is how all versions of vBulletin before 3.5 functioned.
2) Database (no automatic forum marking) - this option uses the database to store thread and forum read times. This allows accurate read markers to be kept indefinitely. However, in order for a forum to be marked read when all threads are read, the user must view the list of threads for that forum.This option is more space and processor intensive than inactivity-based marking. The user must manually log out from DodgeBoard.com to be disconnected. Simply closing there browser will keep there session active and show them online.
3) Database (automatic forum marking) - this option is the same as a previous option, but forums are automatically marked as read when the last new thread is read. This is the most usable option for end users, but most processor intensive. The user must manually log out from DodgeBoard.com to be disconnected. Simply closing there browser will keep there session active and show them online.
The method we use at DodgeBoard.com is the first method. Time-Out for Cookie is set to 1500. This is the time in seconds that a user must remain inactive before any unread posts are marked read. This setting also controls how long a user will remain on Who's Online after their last activity. Some boards choose to set this setting to a very high value like 10,000, resulting in the appearance of more poeple online, when they have actually left hours ago. We feel a setting of 1500 better balances usability and server optimization. As long as a user is not inactive for 25 minutes, they will stay logged in.
The cookie that contains information about your visits to DodgeBoard.com is located in your C:\Documents and settings\%USERNAME%\Cookies directory and is called
%membername%@dodgeboard.com or
%membername%@www.dodgeboard.com
I hope that answers your question, Lurker.
DBA1