My thought would be something like a small LDAP type server. Self-hostable. You make a user like myuser@mydomain.net and its honored as a log in for the various fediverse stuff.
So like it could hold the subsciptions for the communities on the various threadiverse servers you connect to localy, and when you open say lemmy.ml, part of the info sent for your user would be a list of communities you are subscibed to on lemmy.ml.
If it just handles the user auth, then it could also be a user auth for other fedivers stuff too. PixelFed, and Mastodon, etc. Each service could have its own sub section of the user object's info.
You would still probably end up with a "home" instance you would use, but if that home instance becomes untenable, or goes away, then you would just pick a new instance and log in there with your myuser@mydomain.net account.
Im not a good enough dev to code it, but thats my idea anyway.
I've noticed that that doesn't always work. User profile pictures can be NSFW and still be shown. And the 'random' posts box will show NSFW images sometimes as well.
It's something to be looked at to make sure all the edge cases are covered, so that the "show NSFW" check box being unchecked actually does prevent all NSFW stuff from being shown.
I'm not worried about it too much. It's just growing pains as the #threadiverse gets on its feet. The devs will fix it in the code, and until then the user can block stuff manually, which is what I have been doing.
@JeffKerman1999 bring some plans for the printing press and some plans to mass produce paper too. Back in the ancient times one sheet of paper was about $30 in todays money. A whole book would be the equivalant of tens of thousands of dollars.