Interesting comparasons. But a couple of minor points.
Google doesn't innovate new kinds of produts? Not if you think ad-sense / ad-words was a minor innovation on something already available from Yahoo or MS. I wouldn't agree.
Where's Orkut? Surely the basis of a portal. And a comparison of MS, Yahoo and AOL in the social networking space would be interesting.
I think Umair Haque may have a more telling point :
What's really happening in this space? Google has become one of the world's hyperefficient market makers. All these products are just ways to create goods (aka "inventory") to sell on that market, and, by doing so, to raise switching costs on both sides of the market).
Yahoo is not nearly such an efficient market maker. It has struggled to build a market like Google; while it's had some significant wins recently, these have been premised largely on price competition - the fact that Yahoo is a bit cheaper, not that it's market is more efficient.