Nintendo Wi-Fi Connection

Nintendo Wi-Fi Connection is a service built into the Nintendo Wii and Nintendo DS that you can use to play games online with other people from around the world. The feature was first used in Mario Kart DS. In Animal Crossing: Wild World and Animal Crossing: City Folk, by using Nintendo Wi-Fi connection, it's possible for you to visit and send letters to other towns, as well as communicating through the DS microphone or Wii Speak.