What exactly is this "Wii Pay & Play" deal they're coming out with?

Looking for a game for my parents and I to play, I’m noticing that a lot of them are carrying a new orange “Wii Pay & Play” sticker on them. I’ve been doing some searching on it, but I’m getting conflicting results from the various webpages.

What does it mean? Do we now have to pay to play certain games online, or is it more for downloadable content or tournament games?