Just found an article by the developer of Notes. It was 63 messages max.

Remember when they implemented Quoting in Pad, and we had a massive thread of "I get a feeling of deja vu when using Pad" about 20 levels deep. Pad got broken when someone started a thread with "It was a dark and stormy night." It was discovered that while there was a limit of 128 poats (or was it 64?) no one bothered to check if several people were composing after max - 1 had been added. This was before they split Pad up into different topics as Notesfiles. I think I have a fanfold paper listing of some of an sf notes thread floating around somewhere.

Do you mean michelin/empire? Awesome multiplayer Star Trek based game, which I spent many nights on, and which chewed up an impressive percentage of CPU cycles at night. I saw it advertised in a UNIX trade rag in the early '80s.

Definitely. I started on PLATO in 1975 after taking the CS course on it when I was a CS grad student at Illinois. I was a columnist for the Red Sweater News Service - I wrote the Star Trek Preview column, which started describing which Trek the Urbana PBS station was running. I suspect this might have been the first online Star Trek column ever (but I never get invited to any conventions.) I got to keep my login because George Friedman, the CS prof who administered the CS department account, liked my column. Much of PLATO has been implemented - but not term pizza, alas.