In order to improve user experiences with simulation tools hosted by cyberinfrastructure, we endeavor to gain a better understanding of how users interact with tools. The dimensionality of these tools is often too large to be intuitively understood. This paper presents two contributions to the study of user behavior: the MEANDER algorithm for visualizing sessions of user activity, and a scoring method ("searchiness") for characterizing a user's behavior along an axis of "wildcatting" vs. searching. The MEANDER algorithm uses graph heuristics to "squash" a high dimensional path of exploration into a (distorted) plane for rendering. The "searchiness" score is built upon the same graph techniques.
