I am playing around with the barely functional live beta of Google Base that just launched. There's not much there, but what I do see is interesting. At the very least this is going to be serious competition for Ning. Beyond that it may compete with Craigslist and other classifieds and events listing services. It's an interesting first step.
But I also see several potential major problems with the approach that Google Base is taking -- in particular there does not seem to be any notion of real semantics under the hood. Is the data at least available as RDF? But even if it is -- how will it be integrated as everyone starts creating their own types? From what I can see, without data type standards, Google Base is likely to develop into billions of non-integrated data record types -- an unuseable "data soup." Searching across these non-normalized records will be next to impossible without an ontology or some form of higher-level data integration. I wonder if the folks at Google have thought this through? At my own startup, Radar Networks, we've spent several years exploring these issues in our own work and in our DARPA work -- all of which is centered around making use of richer semantics in applications. And we've built a working system that makes this much more practical.
We believe that "the world wide database" requires the Semantic Web as its key enabling infrastructure. The technologies of the Semantic Web (RDF/OWL principally, and perhaps XML Topic Maps as well) enable a truly interoperable, open data exchange layer. From what I can see neither Ning nor Google see this, but they are interesting first steps at least. If anyone from Google or Yahoo is reading this, I would be interested in speaking further with you.