is an exchange for Bitcoin and the UIA GATEBTC. When receiving Bitcoin it issues and distributes GATEBTC, and on receipt of GATEBTC the UIA is burnt, and Bitcoin is sent in response.
What I like about it - Is that it moves away from the idea of needing to use centralized external exchanges like bter and btc38 and instead takes advantage of the decentralized-exchange features of Bitshares to move value around. It's also 1:1 fully redeemable in both directions so there's no confusing spread like there is between BTC/BitBTC. This feature also means that the Gateway doesn't need to play a market-maker role and take complicated market-actions to manage risk due to holding indirect positions.
The disadvantages, are that the private-key exchange between the wallets is too complicated to be practical for the end-user. Although I believe this could be addressed fairly easily with a simple change in design.
Also, as a single node/gateway on the network there is counter-party risk. This could be addressed by using multi-sig wallets and then working out a protocol to perform distributed transaction signing so that multiple hosts(chosen delegates) could perform in the role. But this would be a more complicated to achieve.
For these reasons I'm not actively promoting the site.