I have been enjoying Steve Krug’s brilliiant “Don’t Make Me Think!: A Common Sense Approach to Web Usability”. He mentions that one of the reasons that Groucho Marx was so funny — and successful — was that all of his shows were testing five times a day on grinding Vaudeville tours in front of live audiences. The Marx brothers honed their jokes, writing and re-writing them and focusing on the ones that got the best reactions from real people in the audience. He also mentions that Groucho, even once they’d created jokes that got great responses, kept on testing small differences in the lines to see what had the best effect.
Sounds a lot like usability testing today — using lots of little tests to find out how live people react to a site. Not just what they think about it but what they actually do.