Coyote and Scorpia beat me to it, but apparently a group is interested in bringing the Zork universe into the MMO realm, as reported on Ars Technica. It's to be called Legends of Zork and published by Jolt Online Gaming, a group headquartered in Dublin. There isn't a whole lot of information available yet, though.
From the press release:
"LegendsofZork.com will provide online gamers with a persistent online adventure, playable from any Internet browser. Players take up the role of a recently laid-off salesman and part-time loot-gatherer, as he explores the Great Underground Empire. Designed to provide gamers with a casual MMO game they can play on their laptop, desktop or Apple iPhone (in school, work or on the bus), there’s nothing to download, just go to www.legendsofzork.com."
I have to say I'm not completely surprised, given some of the recent advances in browser-based IF and multiplayer IF. Of course, there is Guncho, a multiplayer IF system based on Inform 7, which was released not too long ago and has received some nice attention, although I haven't spent much time with it. But multiplayer IF is also not exactly a new concept -- it just hasn't been done much.
Most people will think immediately of MUDs and so forth, which is entirely appropriate as a precursor to multiplayer IF but which I'm not sure I would necessarily classify as IF. And others have approached it in the past, notably Mike Rozak, who has both written about multiplayer IF theory and put his money where his mouth is with his graphical multiplayer IF-like system called CircumReality. Interestingly, Home of the Underdogs lists a couple of games under the heading of "Interactive Fiction Multiplayer Titles", but I wouldn't exactly classify them as such (both of them, Fallthru from 1989 and Zyll from 1984, are really just text-based RPG games).
Still, I can't say I've seen anything yet that I would point at and say "Now that's multiplayer IF", at least not until Guncho came around.
It will be interesting to see how they implement this, and I'm not really sure how it will go. It's also not clear if this will be free to play, or if they have some sort of business model for it. I do think there is a potential niche market for multiplayer IF, but I imagine those kinds of games and scenarios would be especially tricky to construct. I'll be keeping my eyes out for this.