This is really just a heads up for anyone who missed it: this year's GDC featured a new post mortem session for the now 20 year old Ultima Online, and the video is already available for free here.
UO remains a source of interesting MMO history and design topics to this day. Although the session featured many of the same talking points as the post mortem in 2012, there was a little bit of new stuff there, too. For example, this time Richard Garriott himself took part, and Rich Vogel talked about the invention of game time cards.
I only wish I could find an interview with Rick Delashmit, the original main programmer of the game. It would be interesting to know for example how they stored world state information and account data on disk back in the day!