I first heard of the concept in Jef Raskin's The Humane Interface. Here's a bit of a survey: http://www.codinghorror.com/blog/archives/000858.html http://www

I first heard of the concept in Jef Raskin's The Humane Interface. Here's a bit of a survey: http://www.codinghorror.com/blog/archives/000858.html http://www.codinghorror.com/blog/archives/000858.html