(Or Web site usability) The study of design and architecture factors that affect a user's ability to successfully perform tasks and solve problems on a Web site. Usability testing frequently involves giving users well-defined tasks and evaluating how different Web site designs enhance or hamper their ability to complete tasks effectively. The test results are then used to improve the usability of the Web site for a specific audience (or audiences). For an example of a usability factor, see action-to-reward.