Years ago, Nintendo Wi-Fi Connection shut down, killing multiplayer for however many DS and Wii games. (absent any fanmade patches to run against fanmade replacement servers)
Later, Nintendo also pulled the plug on Miiverse, thereby disabling everything from cute experimental social features like the messages-in-a-bottle in Wind Waker HD to the functionality of sharing and downloading levels in Mario Maker 1.
Recently the 3DS eShop went offline too, so now you can't even buy digital titles, DLC, DSiWare, etc. any more. (though you still can and should plunder them at sea)
You know what didn't go offline? You know what fundamentally can't even have a temporary outage? StreetPass. As long as there are two 3DSes in the world, Nintendo could go bankrupt and shut down all their servers -- hell, the internet as we know it could cease to be -- and 3DS-toting strangers would still be able to passively share tiny bits of data with each other's games wirelessly when they're near each other.
StreetPass was and is such a neat little thing. But Iwata's passed away, and Nintendo has finally "caught up" with the rest of the industry, and now everything they offer -- even their replacement for Virtual Console -- is tied to a centralized subscription service they'll shut down in a few years, and the game-playing world will wring its hands about lost media and preservation and the games no longer being playable or whatever.
But the little green light will keep on blinking when you go to games conventions.
