Multiplayer in FS9 was just a whole bunch of crap :P I would even say -> there is NO multiplayer in FS9. Only IBNet Player is worth, and offers a real multiplayer experience in FS9 8) The version I tried could not support smoke if I remember well, but the option was available, so I guess it was fully implemented in a later version...
I really hope the final version supports smoke effects while online in multiplayer. If it doesn't, then it's no loss for me as I happy with all the other features of FSX that FS9 [not even with the best payware addons] would never support.
well so far i have only seen one other person in the multi[layer mode and he kept comeing and going didnt get a chance to talk to him but i havent tried multi in my FSX because been busy adding sceneries etc etc