This is not working for me anymore. I tried marking forums read and then go into a forum and read a new post, it's still bold afterwards. I don't like clearing my cookies but this seems to be the only answer.

Edited to add: I never log off FT on my computer, maybe that's why I'm having this problem. I just logged off and it said my cookies were cleared so maybe that will be the answer. When I logged back in, this thread was not bold anymore.