I miss chatting with that! It was so interactive. I wonder if it could be translated to communication between more than two parties. It sure would be interesting to see a prototype of something like that.
I seem to recall seeing people use that around the undergraduate CS lab.
I should have mentioned that what was new (to me) when I was introduced to talk/ntalk was the concurrency of the split screen: both parties just clacking away at the same time
As a user of dial-up BBSes, I had often chatted 1:1 with sysops, nor as a sysop with users. The BBS sysop chat implementations were different/simpler; both parties were typing into the same space. This required manners: taking turns, letting the other people finish their sentence. That's the same like a Windows user being remotely assisted today: you and the remote admin can both move the mouse cursor or type into the same edit boxes.
It's awesome: people complete each other's sentences, or stop typing when the other person is saying the same obvious thing.
You can say " , ... what's that word again ...?" and the other person will help, then you can backspace over that and continue your sentence.
I've not ntalked in probably over 25 years. Sheesh!