I agree it seems weird the guy has been blogging since 1994 (per his Blogger about page) with a whopping 2 posts, yet somehow ends up here on HN? Kinda fishy... also, isn't Azure the polar opposite of the technology spectrum from AppEngine? I would of expected "EC2 here I come" instead.
Azure and AppEngine are much more closely related than either to EC2.
Both Azure and AppEngine are platform-aware and do the scale-out magic for you; you write your code and they make sure it scales (more or less, I'm certain there's still some application-efficiency/scalability rewriting, but you never worry about individual machines, in theory)
EC2 means machine level administration and custom scale-out/scale-up techniques. Not to mention there are load-balancing concerns when you're in the more-requests-than-a-single-machine-can-handle range, although that's above 500/sec for many applications.
