Purely accidental, I assure you. :)
Having tried Googling it a bit, it has certainly been done before, although the several examples I found (@textadventure, @txtadventure) don't seem to have had much staying power.
Updating--at least once a day--is pretty easy, and I'm finding it to be a nice little creative writing exercise, where I can't predict what's coming so I have to be on my toes; I guess the real hurdle is keeping enough people coming back to keep getting input. Fortunately I can drive people there from my webcomic site when I need more. MORE! :d