Usability is a fairly old discipline and I have worked in the field for almost 20 years. But until recently usability was not considered strategic. In fact, usability was given low priority in computer companies relative to their eternal search for more and more features. Most computers around the world are pasted over with yellow stickies that list the magic incantations that are necessary to make the computer do even simple things like drawing a pie chart. The computer industry has mostly ignored usability because it has not mattered much to its business model.
Users pay their money before they get to experience the product in detail.
Only after you take a new computer or a new software product home do you discover that you can't make it draw pie charts. By then, the manufacturer is laughing all the way to the bank and the buyer is left with countless hours of frustration. The Web reverses the equation. On the Web, you start out by experiencing the usability of a site. Only if the site is easy to use will you stay there.