Nintendo Zones are public hotposts where you can connect to the internet from your Nintendo 3DS for free, and without any registration or login. That way, you can use many of the online services on the Nintendo 3DS even when you’re on the go.
There’s also a service called Nintendo Zone Viewer, which allows users to download some location specific content. Unfortunately, Nintendo has put up a notice on its support website, to announce that this service has been discontinued in North America.
That being said, only this specific service is impacted, and the Nintendo Zones will keep on working as usual. Users will still be able to connect through one of the 29 000+ hotspots across North America, in order to access the usual online services on the Nintendo 3DS such as: online game play, the Nintendo eShop, Miiverse, the Internet Browser, SpotPass, StreetPass Relay Points and video-on-demand services.