While paving my way through the blogiverse trying to find familiar people, I stumbled upon Hejip, an old colleague and friend. In his blog about usability, he did mention Joel - who has now become the de-facto usability guru among software developers - Cooper is another. However, Nielsen and Eric do not find too many software takers as they talk about public websites and intranets and not real software applications.
Coming back to Joel and his old blog Its not Just Usability, was affordance of Napster really that bad? I don't think so. There are many reasons why the buttons on Napster are as good as tabs:
1. Position: The position of the button was at the top to mimic the position of the tabs. If the buttons were either on the right or bottom of the screen, Napster may not have a story to tell. Buttons on the right or bottom mean that they are action buttons and are clicked "after" the user feels that the action is complete. These buttons are never perceived as navigational elements. However, buttons on the top and on the left are typically perceived as navigational elements and are not confused as action buttons.
2. Shape: The Napster buttons were rectangular and placed horizontally - the approximate shape and the placement of tabs as we know them. The size of the buttons also was very similar to a regular tab.
3. Mutually Exclusive Affordance: The buttons gave good feedback that only one can be selected at a point of time - only one button (the selected one) was depressed. If any other was selected, the selected become the depressed on while the previously depressed came back to normal position. The affordance of buttons being mutually exclusive was very good.
So tabs could have been better? I don't think so - they would have been as good. Napster confirmed to good Usability principles while using buttons. However, that was not the reason that Napster was popular (Joel would agree too!) - the popularity of Napster solely lies with the usefulness of the software in social settings. Even if Napster's usability was bad, I am sure it would have been as successful.