The Mii Channel is a Nintendo-Propriety Avatar Creator. It is designed to "put yourself into the game" by allowing Miis to play in certain titles. For those titles that support Miis, each mii can be used in that title (ex: Wii Sports, pick a Mii and play as it).
This application was officially unveiled by Nintendo in September 2006. It is incorporated into Wii's operating system interface as the "Mii Channel". Users can select from pre-made caricatures or create their own by choosing custom facial shapes, colors, and positioning. Miis can interact with other Wii users by showing up on their Wii consoles through the WiiConnect24 feature or by talking with other Miis created by Wii owners all over the world. This feature is called Mii Parade. Early-created Miis as well as those encountered in Mii Parades may show up as spectators in some games.
Miis can be stored on Wii Remotes and taken to other Wii consoles. The remote can hold up to a maximum amount of 10 Miis. The Wii itself can hold 100 Miis.