I know that former iterations of both this game and Guitar Hero games provided "expansion discs" or something of that nature to release some of the songs that were available as DLC for the Wii console, since they were unable to be downloaded through some kind of marketplace which was available on the Xbox 360 and the PS3.
However, when loading up Rock Band 3 for the Wii, there is an option on the main menu to procure extra music (although I don't remember the exact phrasing). How does this option work? Is the Wii now capable of the same kind of system that had already been in place on the other two consoles?