I hadn’t heard about JSR-170 before so I did a search on Google and found a presentation on JSR-170 from JavaPolis 2004. The presentation gives an overview of the specification and what it is for.
Looking at the concept of a content repository that JSR-170 introduces, the Domino/DB2 integration again makes a lot of sense. Could this be the promise of one single, all-knowing, all-encompasing content storage facility?
Given that the specification might have changed since you should search for updated information if you need exact information about the specification.