On Japanese imageboards, there is an option to "sage" (pronounced "sageh" I think) where your reply doesn't bump the thread to the top of the imageboard. I think an option like that would be good, allowing people to post replies or comments that they want to, but don't think is important for everyone else to see. When people say "Thanks! That worked!" or other things, that doesn't really warrant the thread being bumped to the top of the list. Sometimes I want to say something like that to someone else, but I don't want to bump the thread to the top.