The name Wikidata is already taken, by the group of projects that aim
to provide reusable static and dynamic facts. So for example, Wikidata
will have a variable for {{population of Spain}}, that can be added to
any Wikimedia project, but only needs to be updated in one location
(or could be tied into an official U.N./Spanish xml feed for complete
automation)
http://meta.wikimedia.org/wiki/Wikidata
I don't know how far along any of the experiments are, or how close we
are to getting it integrated to English Wikipedia, but I'm aching for
it like nothing else...
As for expandable/tangential content sections, I adore the way
Encyclopedia of Life's demo looks. Click the play button at
http://www.eol.org/home.html for the "novice-to-expert slider" about
halfway through. I think that's the lofty target we should aim for.
Quiddity