I remember playing a game 10 years ago called "Bolo", a clever resource-management and arcade-y shooting tank game, multi-player over AppleTalk.
I remember in the release notes, author Stuart Cheshire speculated on the future, saying that future versions could feature 10,000 players in a single networked game, co-ordinating via "battlefield radio" voice chat.
Today, we play EverQuest with tens of thousands of players, and use audio headsets to chat with team-members in online games like SOCOM. So, two big check-marks there. Thanks Stuart!