Nintendo Wi-Fi Connection
The Nintendo Wi-Fi Connection (WFC) service was an online gaming service that provided free access to play in various Nintendo DS and Wii games, including Mario Kart DS and Mario Kart Wii. Nintendo discontinued the service on May 20, 2014, primarily because the host of the service, GameSpy, was shutting down its servers. Nintendo WFC was required for online play, but the Wiimmfi Project has replicated much of its functionality and allows for continued online play in Mario Kart Wii and other games.