vBulletin's WYSIWYG editor didn't support Chrome on this version of vB. (They still considered it just another random webkit at the time.) There's a Chrome extension that will put it in. Just don't forget it's there and start typing before it loads. (It WILL erase your text if you just so happen to type before it loads.)
vBulletin WYSIWYG
It's not perfect, but it works. I personally have gotten used to doing without it. Those dynamic editors have always been buggy for me.