WiimmfiThe Nintendo Wi-Fi Connection (WFC) service was an online gaming service that provided free online play in various Nintendo DS and Wii games. Nintendo discontinued the service on May 20th, 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.
To use Wiimmfi, the games must be patched to use the new domains and also to change some other settings. See »Wiimmfi Patcher« for more details.