So can the information on how you should partition your hard drive for Linux installation. Yet (historically) most people think Linux installation is a usability disaster.

Or for another way of looking at it, do you really think that an interface which requires you to go online (or read a manual) to figure out how basic stuff like undo or delete work represents "good usability"?

Also, as the author points out, what is "refresh" supposed to do in the context of a single message? Just because a symbol is familiar, it doesn't mean its meaning is automatically clear if it's taken out of context. For example, at my workplace recently got a new microwave that has a play/pause button. In this case, it's relatively easy to figure it out but it still gave me a pause.