So it's not actually an API - rather a centralised site for handling ebay-style reputations? With an API?
The core philosophy to this looks to me like an attempt to de-anonymise the currency (and I'm not sure that that is a good thing) by putting all participating payments through a central system (and I'm not sure that's a good thing) in a non open-source/transparent way (and we all know that's a bad thing)... for money.
API is an Application Program Interface, it is a set of commands accepted by a host environment for execution, they have listed it here
http://www.bittrust.org/About_BitTrust_API . The API lacks commands to manage money account, like "check balance" therefore i assume that payments would NOT go through bittrust.org but use bitcoin p2p network as any regular transaction, and i think the command "API - > send money to user" will just show users bitcoin address or something like that (owner of bittrust should step up and explain more about his website so we won't need to guess) .
Bitcoin could really do with some system that allows people to build an ecosystem of applications on top of it... but it needs to be something like The Apache Foundation, rather than someone who looks like they're operating out of a rented mailbox, with a website with self-referencing links embedded in the page - presumably to trick google.
What we need is:
Open-Source
Free
Decentralised
And not just for the simple fact that we don't want another MtGox-style, opaque, single-point of failure going tits-up on us... but also because of the spirit of the thing. The currency itself should be optimised for scarcity, the supporting infrastructure should not be.
So you are asking for unified, open-source and decentralized database that would be used to store and share data between any application in bitcoin ecosystem, not sure if it's technically possible, can't even recall an attempt to do something like that. Could you point me somewhere i can read about it?