As millions of people “search-and-surf “ the Internet, seeking needed products and services or just exploring to see “what’s out there,” businesses are concerned that their Web sites will: (1) attract both searchers and surfers, (2) interest them long enough to thoroughly explore the site, (3) motivate them to purchase their product or service, and (4) encourage them to return to the site and/or recommend the site to others. As the number of commercial Web sites continues to grow at an explosive rate, this competitive market requires effective interface design guidelines and evaluation criteria. Although there are a number of resources that provide guidance on the structure and content of Web interfaces, they typically focus on content. Some focus heavily on content and validity issues (Does it have the right information?), while others focus on functionality issues (Does it work the way it is supposed to?). Few have a theoretical foundation, offer diagnostic methods for assessing and interpreting results, and provide detailed feedback for improvement. Furthermore, few, if any, emphasize the motivational aspects of Web sites, i.e., those features that stimulate curiosity and engage the user’s interest, while providing relevant content and an easy-to-use interface. These features help to motivate customers to visit, explore, and return to a Web site.