Guiding Users with Persuasive Design: An Interview with Andrew Chak
http://www.uie.com/articles/chak_interview/

Perfetti, Christine and Andrew Chak
User Interface Engineering
2003

Abstract:

An easy way to define persuasive web design is to contrast it with usable design. Usability focuses on giving users the ability to complete a transaction if they so desire. A usable site makes it easy for users to complete transactions, from buying products to convincing users to read featured articles. Unfortunately, having a usable web site is not always enough to convince users to transact. Even if a user can complete a transaction on your site, doesn't mean that they will transact. To be successful, sites must go beyond Usability by focusing on Persuasive Design.