Nintendo of Japan announced yesterday (US time), that they will cease online support for the Wii home console and DS handheld on May 20th of this year. This follows the company's decision to end support for several Wii applications back in 2013. Some are already speculating that this may be an attempt to get more fans to adopt to the struggling Wii U. With that said, Nintendo may also be trying to free up their internet servers before Mario Kart 8 and Super Smash Bros., both of which are popular titles that will demand a large online presence, launch later this year.
Games that will be greatly affected by this cutoff include Animal Crossing Wild World and City Folk, Mario Kart Wii, Pokémon Battle Revolution and Pokémon Black and White. A full list of games and applications can be found alongside the announcement on the company's site. With that said, local wireless will probably still work after May 20th.