Well, it's sort of dead.
There was the original game, which took the RPG world by storm about 10 years ago. It was a lot like Shadowrun mechanically (and gameworld wise, actually), only instead of using just d6s, it used all sorts of dice. It also had 10 stats instead of S-Run's 6.
I thought it was okay (I like dice pool games), but that it was too complicated, because it had too many different attributes and I hate games that have a lot of dice types for skill rolls (it's confusing)
I think there were two editions of it.
Then there is the d20 version. I liked it a lot, but I seem to be the only one. The splatbooks for the d20 system were poorly designed mechanically, though, at least the prestige classes.
I don't think it sold all that well, or less then they expected (I think they had unrealistically high expectations - the original Deadlands was a huge seller). They then came out with "Savage Worlds", sort of a multi-genre gereric game system. They are supposed to be making a Deadlands book for that.
Like I said, I thought the world was a lot like Shadowrun, like our own, except that magic came back in the 1860s, not 2011. And it was eviler.