Internet communications in general and the World-Wide Web specifically are revolutionizing the computer industry. Today, the Web is full of important documents and clever applets. Java applets and servlets are beginning to appear that provide useful and even mission critical applications. From the perspective of simulation, a future Web will be full of simulation models and large amounts of simulation-generated data. Many of the models will include two or three dimensional animation as well as virtual reality. Others will allow human interaction with simulation models to control or influence their execution no matter where the user is located in the world. Analysis of data from Web-based simulations involves greater degrees of freedom than traditional simulations. The number of simulation models available and the amount of simulation data are likely to be much greater. In order to assure the quality of data, the execution of models under a variety of scenarios should be well managed. Since the user community will also be larger, quality assurance should be delegated to agents responsible for defining scenarios and executing models. A major element of simulation analysis is the analysis of output data, which controls the execution of simulation models, in order to obtain statistical data of acceptable quality. Such data may be used to predict the performance of a single system, or to compare the performance of two or more alternative system designs.