Reply to and closed topics
If you don't have an account, just leave the password field blank.
I find those annoying. Cause if I'd like to reply to a message in a closed topic, I would have to start a new post, and then put a reference to the closed post in order to reply. I haven't done that yet, cause it feels rahter lame and useless, but I may start doing it, cause it's the only way for me to make my reply it seems.