I'll tell you a secret: what I like about this blog is that I can say stupid things, or small parts from the truth, and then other people may tell the truth or share the whole picture. And it's not that I intentionally say stupid things or parts of the truth.
When I wrote Download Google Videos as AVI, I heard that Linux users had a direct link to AVI files in Google Video. Then I looked in the code from video.google.com and discovered that Google hides the link from Windows users, so they have to download Google Video Player. I really like bookmarklets, so I made a simple one to launch the download of the AVI file. And it seemed OK. But people started to say they can't play the video. Then I realized that the video works only in Media Player Classic, MPlayer, but not in Windows Media Player. The real problem was that Google adds a small header in the file, and most players (including WMP) don't like that.
Then I found (in the comments of the post) a really nice site that has a lot of tips about downloading videos from Google Video, YouTube and other video sharing sites. It even has a super-bookmarklet that works with all these sites. There are also utilities that remove Google's header and transform the video into a regular AVI file. My favorite converter is GVI2AVI, a small portable software (44k) that requires the .NET Framework.
What I wanted to say in this post is that you can make a small step and then discover that others have already discovered the whole truth. But that's OK, everybody's gotta learn sometime.