I wrote a short essay (http://kid666.com/2009/12/15/your-users%E2%80%99-mental-models/ http://kid666.com/2009/12/15/your-users%E2%80%99-mental-mode...) about th

I wrote a short essay (http://kid666.com/2009/12/15/your-users%E2%80%99-mental-models/ http://kid666.com/2009/12/15/your-users%E2%80%99-mental-mode...) about this for "Designing Social Interfaces" (http://www.amazon.com/Designing-Social-Interfaces-Principles-Experience/dp/0596154925 http://www.amazon.com/Designing-Social-Interfaces-Principles...) by Christian Crumlish and Erin Malone.