Nintendo Wi-Fi Connection
Nintendo Wi-Fi Connection, or WFC, was a service from Nintendo that allowed Nintendo Wii and Nintendo DS games and applications to connect to the Internet. Super Smash Bros. Brawl was one of the many games that had compatibility with the service, using it to allow for online brawls with friends or with anyone; in addition, players could also exchange some data with each other with the service.
The service was later superseded by the Nintendo Network for the Wii U and 3DS, though the Nintendo Wi-Fi Connection continued to act as a legacy connection for the Wii and DS consoles; both the Wii U and 3DS had only limited compatibility with the service.
With the shutdown of the network provider GameSpy, the service went permanently offline on the 20th of May, 2014. Hacks, however, have been developed to allow players to continue playing compatible games via private servers. The Dolphin emulator is currently the most popular method to play Brawl online, many times with mods.
The Nintendo Wi-Fi Connection allowed players to play against each other online for the first time in the series. A primary point of this was that it allowed players to either play with anyone in the world or with registered friends. The former, With Anyone, allowed players to either take part in standard free-for-all battles via Basic Brawl, or to play as a part of a team in Team Battle.
In addition to allowing for online gaming, Brawl also allowed players to send replays, custom stages, and snapshots to other players with whom they had registered. An applied use of this was the Smash Service, a free service that sent players a replay, a custom stage, and a snapshot each day; these pieces of data came from submissions of players, and were deleted at the end of the day.