Why does it do that?
 

All my messages get marked as read a lot, and I don't mark them all as read. Half the headlines were bolded in black, I go to the bathroom, come back and the threads are all marked as read, even though I didn't read most of them. What gives?

I don't know what the time limit is, but after awhile of inactivity, the threads that have new posts in them will be un-bolded like you've read them. I don't know why it does that, maybe the cookies expire. I'll direct this to the main chickie. :)

It's based on browsing sessions and not actual read threads. Unfortunately, that's the way it was programmed and there's nothing we can do about it :(