a lot fo online forums do not allow html tags (or don't recognize them or don't process them - however you want to say it). MWK does. at least for links, italics, bold, underline, strikeout -- the basic stuff.
Which I find FANTASTIC! It's a lot easier for me to type the tags in as I go then have to hightlight and click - or remember that I have to use different brackets -- and differrent code for links, etc.