Web as a platform "is a non-starter.  If I write a mashup using data from three sources, I'm relying on the reliability of all three of those sources (which opens me up to a lot of risk that I have very little control over).  Given that I may be competing with one or more of them (if I make their data more valuable, I'm probably taking some of their users), they don't have incentive to continue providing me with data reliably, unless they start charging me for the data"