sorry to reply to my own post but I had some further comments:
That YQL is a middle man between the consumer and provider of the service is another huge issue - latency is a big enough problem for any web app without having to funnel everything via a query to Yahoo first.
That YQL is a middle man service is also a huge risk to scalability.
Finally, YQL makes it clear that the web does have a need for such a standard - the fact that Yahoo has not made it an open standard simply means that other organisations will do the same thing, but as an open standard, which will probably be the end of YQL - a missed opportunity for Yahoo.
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