http://en.wikipedia.org/wiki/Projection_bias
The author assumes that because he doesn't know what he's doing, other people also don't.
I disagree. Sometimes people can know exactly what they're doing, and be fairly confident about the possible consequences.
I made a viral hit similar to the author's YT instant, and I very much did not know what I was doing. Then I did it again with different code, without leveraging the existing user base, just to see if it was all luck. It wasn't. I think a better argument would be that "sometimes successful projects are successful by accident", but that would make a terrible post title.