We collected traces of how 37 users interacted with 9 progressively streamed and rendered 3D meshes. We analyze the traces and discuss the insights that we learned in relation to design of efficient and scalable progressive mesh streaming systems. Our traces indicate that user actions are predictable and exhibit skewed access pattern. This finding could lead to design of efficient pre-fetching and caching techniques for progressive mesh streaming. Categories and Subject Descriptors I.3.2a [Graphics Systems]: Distributed/Network Graphics General Terms Human Factors, Measurements, Performance Keywords Progressive Meshes, Interaction, User Behavior