A slew of technical writers and journalist that I've met use it all the time. Since I'm not in either occupation I have to believe it's true. In fact, it almost holds water all by itself. The content of a web site could be great, but if the navigation is poor, then the user will bail by clicking the 'back' button. A zillion clicks means a zillon page loads and that's just to painful.
Navigation is important to the surfing community.
Okay so the content stuff is really important, but it's like a single celled creature. It must have a healthy environment for it to live. It's what helps a reader know where they are and make decisions on where to go using a particular communication device. For watching TV a person has a remote control device to navigate sitcoms, cartoons and other shows. For reading books a person has chapter headings and page numbers to show them where they are.