HTML/JS insertion wasn't anything I ever intended for, but it turned out to be a really neat feature/bug.

You can do almost anything by inserting a little JS, like inserting an image, changing thread background or styling text (something that would normally be done in bbcode/etc). And among other things, if you don't like a thread, you can "close" it with <!-- or redirect it elsewhere.

I think this would be a really interesting feature on a "real" message board (albeit with some constraints)