Wii Shop, DSi Shop and third-party video services will remain active.
In-game services that use Nintendo Wi-Fi Connection on Wii and DS will be shutting down as of May 20, 2014.
Nintendo has announced through their official Japanese website that after nearly 10 years, the Gamespy-powered online service, Nintendo Wi-Fi Connection, will be coming to an end. The Wii Shop Channel, DSi Shop Channel, Internet Channels and third party video channels such as Youtube will remain active, but all other online features, such as online multiplayer and unlocking content via connecting to the internet, will no longer be available.
We have yet to learn if Nintendo WFC services will be ceasing in North American and PAL territories as well. UPDATE: Nintendo of America has confirmed that WFC functionality will be ending in North America as well.