Forum system - how to track already read vs new messages, per user

[eluser]TheFuzzy0ne[/eluser]
I agree. I think you just need to track the thread (and forum ID), and the date/time it was read. That way it's very simple to know if there are any unread posts for a thread, because the thread will contain a post where the date/time is a higher value than the one stored in the tracking table.