The easy (and tired) joke to make is that WoW was the first MMO, but there were plenty of ambitious multiplayer games that predate even Ultima Online and EverQuest. In fact, readers of our own Game Archaeologist know the list of proto MMOs is long indeed, and now some of them have been outlined in a fun history video put together by YouTube channel Computer Gaming Yesterday.
The video is intended to shed light on the games that pioneered our favorite genre that have otherwise been lost to time and memory, including Habitat; the original Neverwinter Nights on AOL; Kingdom of Drakkar, which comes from a MUD called The Realm; the online dungeon crawler The Shadow of Yserbius; and The Realm, which incidentally has no relation to the MUD of the same name. The video even provides links in its description where MMO fans can play emulators of a few of these classic titles.
For those who are curious about tracing back the very early days of MMORPG gaming, this video is an excellent resource and has even gotten a Raph Koster seal of approval. Feel free to enjoy your gaming history lesson after the cut.