One of the reasons I'm so attached to that stuff is that DGD, the server I use for my MUD stuff, is an absolutely crazily cool little tool. It does some frightening things, and I don't know of any other language that does them. This is one reason that callout to other languages from DGD can really suck :-)
Anyway, a lot of those features are geared toward a persistent server - a server that runs as though it never went down. If anybody with a strong technical bent and (for preference) no real experience with DGD wants to look over an in-depth explanation of what that means, and how it impacts your programming model, I've written a summary. It also happens to read like a tour of DGD's weird and unique features, though it actually skips the ones that sold me on DGD originally :-)
That's okay. There's plenty of time to write a summary on those, too. I've just depressed myself by doing line counts and character counts, and it turns out I've typed about a megabyte of stuff for this site, over the years. Over 25,000 lines. That's not counting the binaries, the external stuff I've downloaded and placed, the cut-and-paste mailing list messages...
That's, like... That's a novel. It's not really even a small novel.