I don't see the similarity at all. Wolfram Alpha gives you detailed information about one thing. Google Squared gives you general info on a things in a category.

This fits right in with Wolfram|Alpha. In order to produce all the amazing comparisons Wolfram|Alpha they had to turn databases, and the public web into structured data sets. What would make this much more then novel is if the collected data sets were made public or licensed for academic use. I'm hesitant to say commercial use because a) they can already do that and probably will, and b) it's the public assisting with collecting the data. One problem with Wolfram Alpha that a user submitted structured data will not solve is the ability to cite sources (or provide some reason to trust the sources). Wolfram Alpha has created a bunch of it's own datasets and academically you just have to "trust them".

And Yahoo YQL

There is no relationship at all. YQL is just a way to query disparate Yahoo data sources with a relational-like language.