I agree, but I don't think that was the focus of this article. No amount of usability testing would have helped here. RWW and Facebook already look completely

I agree, but I don't think that was the focus of this article. No amount of usability testing would have helped here. RWW and Facebook already look completely different - not the URL, the entire page! The same goes for any other application. The user doesn't have an appropriate "mental model" of how the computer works. What is an app developer to do at that point?