Battle.net
Battle.net is an online gaming service provided by Blizzard Entertainment.
Unlike other popular online gaming services, the Battle.net connection fees are included in the list price of the game.
This has made Blizzard's games wildly popular since they cost nothing extra to play online other than Internet connection fees.
A group of gamer/programmers produced a freely available clone of battle.net called bnetd. Blizzard games normally only work over the Internet with battle.net, but bnetd allows gamers to run their own private server.
In February 2002, lawyers retained by Blizzard threatened legal action under provisions of the DMCA against the bnetd developers, and the project was officially halted. As of June 2002, Blizzard lawyers were in negotiations with attorneys from the Electronic Frontier Foundation to resolve the case without a full trial.
How battle.net works
Battle.net isn't really an online gaming service like most. It's actually a matching service. The only (for lack of a better word) big data hosted on battle.net is player records as opposed to the gigantic size of files for other online games (such as Final Fantasy XI or any other MMORPG).
List of battle.net games
