Anybody here used pre-BBS social networks, like PLATO?

Since the subject of BBS has been raised, I wanted to mention BBS-over-teletext, which used the bidirectional CATV connection: https://en.wikipedia.org/wiki/Teletext#Uses They never took off, owing to the difficulty of typing with a remote control, but at least they did not hog the phone line, or rack up a bill.