It does seem as though Nintendo of Japan has decided to put off its Nintendo Wi-Fi connection for some of its older (albeit still popular) consoles out there, as the Nintendo Wi-Fi Connection does seem to be on schedule to turn off access to multiplayer gaming in addition to a slew of other as well as plenty of the other services this coming May 20th. Apart from that, there is the free Video app which launched for the Nintendo 3DS in 2011 that will be unplugged at the end of March. As for the services which will continue to have their wheels greased on the Nintendo DS after May has come and gone would include the DSi Shop, DS Browser, and DSi Browser. As for the Nintendo Wii, it will keep Hulu, Wii Shop Channel, Internet Channel, Delivery Channel and YouTube.
Apart from that, newer Nintendo Network games which arrived around the Nintendo 3DS and local multiplayer would apparently remain in place, but if you happen to have a long-distance score to settle in Mario Kart DS, it would be prudent to schedule a match between now and May 20th, and why not perform a video recording of it for posterity’s sake. [Press Release 1 & 2]