This definitely seems interesting, but I have a few concerns that would make me think that the system is fubar :

The network finds, in average, 1 block every 10 minutes (and it's often less because the difficulty only resets every 2 weeks).
A block should be found, in average, after 600 of your shares. So that's pretty much 1 share per second to announce to all the miners !

That's an awful lot. If you want it to be decentralized, you can't just send your share to one server, you have to send it to everyone, and that P2P-style like propagation induces latency. And because there's a new share found, in average, every second, you're going to be computing outdated work most of the time. If we consider that it takes 500 milliseconds to announce a share to all the network (and that's a very optimistic estimate, most people don't have very high-quality internet connections), you're effectively going to waste 50% of your work time.

I could be wrong, though, if shares don't have to includes the hash of the "previous" share like blocks do. But, why call it a chain then ?

Also, you claim it to be mostly decentralized at the moment, yet you handle the payouts. How do you ensure the generated shares only give the 50 BTC to you ? (Ie, a malicious miner that finds a "winning" share could keep it for himself and take the 50 BTC). That needs an explanation in my opinion.