The story is that Danny Lohner & Charlie Clouser(NIN) had pieces of music stored away, dating back to "The Downward Spiral" days.
They felt that although the music wasn't right for that album, it still deserved to be heard. So they set out to find people who would contribute vocals to the pieces.
"Vacant" is already a classic track in my opinion.
Besides, I think it's about damn time we had something worthwhile to look forward to.