Many years ago, there was a battle between Sony Betamax and VHS for the video tape standard. Beta was technologically superior, but it lost. Why - because of usability. The tapes were not long enough to hold a full length movie. Had Sony done a good job of understanding user requirements, they would have realized that interrupting a movie midstream to change a tape is a dealbreaker.
Well, Sony seems to have learned its lesson. In the Blueray HD-DVD war, Sony has won. Toshiba announced today that it will stop making HD-DVD players. Even though HD-DVD is technologically superior (by most accounts), Sony signed up more studios for Blueray. Variety is also a user requirement. In the Era of the Long Tail, users want access to as many movies as possible.
Yeah for usability!!!