yes, several have, you use commands like
send net message memblock player_number,memblock_number
net message memblock memblock_number
you use commands like these to send the numbers that show the position of the player and what he is doing to the other players, so that the computers can update the view of the other players to reflect what you did, be it just shot them or if you gave em a huge cake with candles on it
, you can also send files, models and sounds over the net to the other machine, so if you had a map the other player didn`t you could send it to them, all sorts of stuff like that, just don`t ask me to list it all
cheers.
Mentor.