The Nintendo Wireless Fidelity Connection, commonly known as Nintendo Wi-Fi Connection, Nintendo WFC or simply WFC, was an online play system incorporated into the Nintendo DS and Wii. It allowed online play on games such as Wild World and City Folk. Wild World was the second Nintendo DS game released that used the Nintendo Wi-Fi Connection, the first being Mario Kart DS.
The system allowed a maximum of four players to be in a town at any one time. Players could either visit other people's towns, or invite guests to come to their town. Before a player could visit other towns or have visitors in their town, it was necessary to exchange Friend Codes with the other players they wanted to play online with. A town could be visited unless both players had entered each other's Friend Codes. It was also possible to register other players while in a friend's town, without needing Friend Codes.
To activate the Wi-Fi Connection, a player had to enter the Town Gate and talk to Copper. The first time this happened, a player was given their own Friend Code to share with other people. Once some friends had been registered, Copper would give the option of either going to a friend's town, or opening the gate and allowing friends to visit. When a player visited a town, gameplay stopped briefly and all other players' screens showed the character entering the town. The same thing also happened if a player left a town. Players could not enter or leave if one player was having a conversation with an animal or other non-player character. While in the same town, players could chat with each other by entering text, or using Wii Speak.
The game was automatically saved when the gate opened or when a player entered or left. The town owner could also choose to save at any time, or could select 'Party Over' to make all visitors return home. If one player turned off their system, or disconnected from Nintendo Wi-Fi Connection for any reason, all other players would be presented with a blue screen saying the connection has been lost, and the game would then reset. Mr. Resetti did not normally appear after a disconnection.
On May 20th, 2014, Nintendo discontinued the Nintendo Wi-Fi Connection service, thus terminating online functionality for Wild World and City Folk as well as many other games outside of the Animal Crossing series. However, Wii homebrew developers have developed a second, third-party server called Wiimmfi, which modded Wii and DS consoles can connect to, and allows certain games to be played online even after the closure of the servers, City Folk included.