I saw someone ask about this the other day. There's some work on a project called Pretendo that's designed to work as an open source replacement for the 3DS and Wii U online services. It's not fully up and running yet but you can see where they're currently at on the site.
Only games uses Nintendo servers, and, as other comments says, Pretendo will replace them. If you're talking about homebrew apps themeselves, they will not be affected.
It means all online Nintendo service will be unavailable for the 3DS and the Wii U.
So, the eShop and online game servers will shut down. You won't be able to purchase any game digitally, and online multiplayer in games will not work. Neither DownloadPlay, probably, but I'm maybe wrong there.
Homebrew, fortunatelly is not provided through any of these channels and they are not dependent on any online Nintendo service.
The eShop already shut down a few months ago though.
oh, you are right, forgot about that
I haven't been here on the 3DS scene for awhile, but if there isn't already, there will likely be homebrew replacement for at least the important online services
Idk much but besides setting a time limit for reverse engineering I doubt it'll change much, don't take my word for it tho
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