By measuring the stickiness factor of a Web site before and after a design or function change, the marketer can quickly determine whether visitors embraced the change. By adding purchase information to determine the level of stickiness needed to provide a desired purchase volume, the marketer gains an even more precise understanding of how a site change affected business. An almost endless number of factor combinations can be created to provide a quantitative method for determining buyer behavior online. First, though, the marketer must determine what measures are required and which factors can be combined to arrive at those measurements.