It is actually pretty interesting points, but he's not the first to make them.
Tim O'Reilly has been speaking about the problems involved with things like Amazon and Google for quite a while. They are basically built on open source software and huge proprietary databases with customized frontends.
AOL and Yahoo have open-sourced several pieces of software, AOLServer among them. Yahoo contributes regularly to the development of the open-sourced Python language, which they use for rapid prototyping and for several of their services.
he does have a point with Google, though. Amazon isn't really a "software"-type company, so I don't see them in the same light.
it's also kind of funny a MS programmer is saying this stuff, given how much code they've taken from BSD sources before and how they don't like releasing things back under that license.
one of the things MS REALLY hates about open source software is that there is no monetary "air supply" to cut off, at least not in the way there are with other companies.
so, the more OSS/Free Software developers are dependent on money supplies they can cut off, the better off they think they are.