I'm not sure if this is a bug or not because i've only started playing AO a week ago. WHile holding down on W to move forward, if u hit enter to bring up the message bar then let go of w you'll continue to walk/running. Jumping will stop it. You can turn off hte message bar by hitting enter again without stopping hte walking/running thing. I found this espeically useful in traversing out door terrain. You can also use this trick to do a whole bunch of other actions like strafing, and moving backwards.
If this is an unforseen bug or something, I;d hate to see it removed because it's actually fairly helpful