So fundamentally the approach we have taken is to build a registry/repository based on REST concepts. And as we looked at the REST space, we kept noticing how close the Atom Publishing Protocol (APP) is to our needs, so we’ve made that the public remote API to access the repository. Of course, if you are just browsing the registry, you only need a browser - APP is mainly there to support updating resources.
The Systinet registry heavily relies on RESTful HTTP, too, but it’s still great to see this. If the road to acceptance of REST, Atom and AtomPub in hardcore SOA camps leads through the metadata use case first, that’s perfectly fine by me.