Usability testing is a widely used technique to evaluate user performance and acceptance of products and systems. It was introduced in the late 1980s and rose to popularity in the past decade. This paper provides a view of the current status of usability testing as a method and describes how it will be used in the 21st century. Although usability testing may not be the most efficient technique for discovery of usability problems, it is a reliable way to estimate quantitatively users' performance and subjective satisfaction with products. Four major trends in usability testing include: common reporting formats and methods for industry; Internet application and website testing; testing of mobile, handheld devices; and testing in more naturalistic environments such as simulated homes and classrooms. In the 21st century, 'quick and clean' usability testing methods are needed to provide valid and reliable data on how well people use products and systems, and how they like using them.