From a recent (4/29/99) interview:
Lomax: Above, you said that you were "no damn good at writing short stories". What about these days? Do you think you will write exclusively in the long form? Oh, and what's the deal with the Big U. Will that ever see print again?
Stephenson: I still find short stories very difficult to write, and I admire people who can do that. At the moment, novels are working for me and so I think I'll stick with them. Concerning the Big U… It is an okay novel, but I'm in no hurry to put it back into the world. There is a lot of other good stuff that people could be reading.