The current default "Hot" is very confusing. First of all, I have no idea what makes a thread "hot" since threads with lots of posts and lots of recent activity don't always show up on the Hot list. Second, if I don't realize that I'm in Hot sort mode then it can lead to situations like today where I spent several minutes searching for a thread and not finding it. It was on page on of the "last activity" listing, but was buried somewhere beyond page 5 of the "Hot" listing so I never saw it and thought the thread had been deleted until I finally remembered to use the forum search feature (which I'd never used before). Having last activity be the default sort order would make so much more sense to me.