I left a comment on Jeroen Ticheler's blog, recommending Atom over RSS 2.0, which seems to have been eaten. Coincidentally, Dan Cohen reminded me today about the new ORE specification and its Atom serialization. I think there are some good lessons in ORE for the geospatial respository people. Atom as a format is one.
We have some graph-y plans for the resources of Pleiades and related projects that fit perfectly with ORE.