The Uncanny Valley of user interface design →

http://billhiggins.us/weblog/2007/05/17/the-uncanny-valley-of-user-interface-design/

Bill Higgins:

So I’d recommend that if you’re considering or actively building Ajax/RIA applications, you should consider the Uncanny Valley of user interface design and recognize that when you build a “desktop in the web browser”-style application, you’re violating users’ unwritten expectations of how a web application should look and behave.