Maze introduced the concept of "online players" in 1973 and muds prior to this lucasfilm example and compuserve had some crazy innovations in the 80s.<p>I’d argue this concept has been happening since almost the earliest days of networks.<p>Wikipedia’s history on virtual worlds is a great resource on the subject:<p><a href="https://en.m.wikipedia.org/wiki/Virtual_world#:~:text=Maze%20introduced%20the%20concept%20of,in%20university%20and%20research%20laboratories" rel="nofollow noreferrer">https://en.m.wikipedia.org/wiki/Virtual_world#:~:text=Maze%2...</a>.