UO was definitely a new direction, considering for online you had MUDs or limited graphical games like The Shadow of Yserbius. However it was quickly eclipsed

UO was definitely a new direction, considering for online you had MUDs or limited graphical games like The Shadow of Yserbius. However it was quickly eclipsed by Everquest which came in 99 and I would say is far more important to the MMO landscape than UO ever was. Asheron's Call quickly followed EQ and while it never had the numbers was the first no zone MMO - you could travel anywhere and no load except into dungeons which were nothing like what people are used to today. It was certainly a time for experimentation to see what players liked and disliked and for all sorts of fun bugs if not exploits in each game to rile a community.