Now, I wonder what qualifies as an online game service. If I play correspondence chess over email, would the email host be running an online game service? If someone modifies the Battle of Wesnoth network code to run over IRC messages, would the IRC host be running an online game service? (What about decentralized network game protocols?)
Lots of legal grey areas to explore, like with Phil Zimmerman putting the PGP code in bookform. I'm sure you could find a way to game online without relying on an online game service.