JAAMan pointed out to me that the old Mega-Tokyo was better about remembering what you've read or haven't read. PHPBB by default will just give you an option so see what is new since your last visit. I've added a PHPBB modification so that the board actually stores what posts you've viewed in the database. You'll also see an icon to unview a post now too. Now it will not matter if you switch computers for those of you that are trying to read all threads.
Let me know if there are any problems....If you're logged in right now you might need to log out to get everything working correctly.