Ive not looked into it so I don't know what kind of challenges they face. Theoretically, I don't see where the problem is though..

The primary input is a users "wishlist" of things they want. Each thing is then compared against a master list which confirms it exists and when it should be available (metadata). This is optional, but offers a more rich experience. Lastly, each thing is queried against a torrent index to try and find it. Its a relatively simple procedure. I guess the only question is whether books appear on these indices or not.

After a quick glance at the notice on their site, it seems metadata was the problem.. or more precisely, no work was being done to move to a new provider. It kinda reads like they lost steam and stopped developing it.