This looks like a lot of fun:

http://www.irata.online/

This fascinating experiment in retro-computing brings online a system based around the archaic PLATO computing system, which was a pre-cursor of the Internet and in many ways a pioneer of features we, even still today, take for granted:

https://en.wikipedia.org/wiki/PLATO_(computer_system)

PLATO featured a Multi-user, subject-ordered messaging/bulletin system, built-in development tools, graphics and hypertext before they were even a thing...

Most fascinating to the average HN reader, perhaps, might be the docs - here as example of the tenacity of a forgotten era, an intro to the TUTOR programming language, around which PLATO is based:

http://www.irata.online/assets/Introduction_to_Tutor-937ef6097482f2c79f790977c80516e1bd11bb52178baec607a4c34860b3969b.pdf

Could we resurrect these technologies in this day and age, and thus solve ourselves the Facebook problem? Perhaps there are gems yet to learn from these pioneers ..