So, for some reason, the 'unread topics' button keeps giving me posts that I've already read, including posts I wrote!  What gives??

 Sometimes theres a lag...

 Also, if someone edits even a period on their post, it will show up in unread, I believe.

Oooohhh...I just assumed it was the last post that was 'unread'. I didn't even think about people going back and editing.  K, thanks! :-D