It really is sad for Miiverse to end like this, but I've come up with a simple way to keep in touch with your Miiverse friends. I call it, operation STCATNOC. (Spell STCATNOC backwards) Let me explain.
You make a post saying "Here's my STCATNOC" or something along that line, and list your pages of sites you have; like Twitter, Deviantart, YouTube, or any online site. But ONLY list the names of the pages; not the sites they're on. Then you tell people to copy them, write them down, or do whatever. Just as long as they have the names for later. And that's it!
I know people are already doing things similar to this, but I have a good feeling about this idea. But we all need to spread the word and explain what this is. I have friends on Miiverse I don't want to lose. And I know I'm not alone. So tell your friends and pass it on. Good luck!