I think your Seti & PP are particular kinds of examples where they already have the data. So it is interesting from the point of view whether it is cheaper to ship the data somewhere else perform your own computations, but doesn't really have much to do with the semantic web, which as I see it, is much more about some form of machine understanding of data so that some undetermined alaysis can be performed on it. Specifically, analysis by people who don't create or control the data.