To satisfy potential customers of a Web site and to lead them to the goods offered by the site, one should support them in the course of navigation they have embarked on. This paper presents the tool STRATDYN, developed as an add-on module to the Web Usage Miner WUM. WUM not only discovers frequent sequences, but it also allows the inspection of the different paths through the site. STRATDYN extends these capabilities: It tests differences between navigation patterns, described by a number of measures of success and strategy, for statistical significance. This can help to single out the relevant differences between users' behaviors, and it can determine whether a change in the site's design has had the desired effect. STRATDYN also exploits the site's semantics in the classification of navigation behavior and in the visualization of results, displaying navigation patterns as alternative paths through a strategy space. This helps to understand the Web logs, and to communi...