The (preview) version of Swivel shows signs of promise. Serving as a sort of "data clearinghouse," Swivel allows users to upload and download datasets and graphs, as well as rate them according to their quality.
Of course, not all datasets are equally useful, but as first efforts go, this is not bad. The ratings help us to sort out the irrelevant, but I suspect we'll begin to see limited membership groups (e.g., subscription or credential-based) emerge over time, as well.
I find it difficult to imagine a world 20 years from now where this sort of service isn't commonplace. It may take another 5-10 years, but (social) research is about to make a qualitative leap forward.