My original reaction to this game was that it was an awesome piece of technology and an interesting piece of game design, but I couldn't see how it was sustainable.
After being notable for one of the only MMOs ever to go back into beta from a launch (though Final Fantasy XIV is sort-of doing that at the moment), Glitch is finally closing.
It did innovate in a lot of areas. It was one of the only MMOs where you can actually drop items, and have some effects on the game world (including building stuff on your home streets). It also had the best crafting interface I've yet seen in an MMO in that if you are trying to make an object, and that object has another craftable object as a requirement, you can make the second object in the same UI and so on.
However, it does show that if a game has too high a running cost, the wrong technology and just not enough players then it's not going to be viable even if it is unique.