Use @domains to allow automatic DTD assembly via "registry in the cloud"

This idea actually predates DITA 1.0.

Even before DITA 1.0 was approved, there was a hope that common @domains tokens would be registered, likely at OASIS:

1. An organization would come up with a useful specialization.
2. They would share it, and "register" the token like some form of Public ID
3. Tools would be developed that would automatically integrate chosen domains from the registry, or automatically create new document types with known modules

All just a simple matter of programming, right?

This idea was discussed before DITA was donated to OASIS. The first reference I found in the OASIS email archives is from 5 April 2005, a couple of months before DITA 1.0 became a standard. It was officially proposed as part of DITA 1.1 on 18 October 2005. And then … nothing.

11+ years on, there is no registry. We haven't agreed on a place to share non-OASIS domains, much less register them in a way that is useful. This should no longer be an argument for using @domains.