Personal bulletin boards won't return without a good reason
I keep waiting and wondering when the store-and-forward network based on computers run by individuals will come back into vogue. It's currently out of fashion given that so many people currently give all their data to other companies, but who says it has to stay that way?
Back in the days of dialing up BBSes, a great many systems had some form of inter-system communication. There was Fidonet, the proprietary GT network, RelayNet, and still others based on slinging QWK bags around.
If you were just a user, you were reliant on the sysop of whatever system you dialed into, but you had a lot of choice in the matter. If someone wasn't being friendly to you, odds are that you could find some other way onto the network.
In those days, running a BBS took a certain kind of commitment. You had to take a capable machine, a modem, and a phone line, and make them available for other people most of the time. You also had to have that particular gene that makes you want to run software that really was not very friendly most of the time.
Today, things are different. Many people have computers in their homes which would be more than capable of running a small bulletin board type service. Instead of needing additional phone lines, it would just need a small amount of bandwidth. Given the widespread switch from dialups to "always on" connectivity in the past decade, that's also no big deal.
Despite all of this, the software really isn't there. There isn't an obvious way to host a small personal "space" on your own machine and make it available to select individuals. There's also no demand for it. Only serious hard core nerds would want to do this sort of thing "just because".
For it to really go anywhere, there has to be a use case. The existing services (Twitter, Facebook, ...) do things well enough to where nobody really cares about alternatives. There is no killer feature which would compel someone to seek out this kind of system. Sure, everyone talks about avoiding censorship and filtering, but nobody actually acts on it.
Until actual draconian restrictions appear and start making it difficult to accomplish things, nobody will move. That's human nature and you just have to accept it.
Just because it can be done doesn't mean it should be done. It also doesn't mean anyone will care if you go and build it anyway.
Update: this post made it to Hacker News. (Thanks!)