We present the Rizzo, a multitouch virtual mouse that has been designed to provide the fine grained interaction for information visualization on a multi-touch table. Our solution enables touch interaction for existing mouse-based visualizations. Previously, this transition to a multi-touch environment was difficult because the mouse emulation of touch surfaces is often insufficient to provide full information visualization functionality. We present a unified design, combining many Rizzos that have been designed not only to provide mouse capabilities but also to act as zoomable lenses that make precise information access feasible. The Rizzos and the information visualizations all exist within a touch-enabled 3D window management system. Our approach permits touch interaction with both the 3D windowing environment as well as with the contents of the individual windows contained therein. We describe an implementation of our technique that augments the VisLink 3D visualization environment to demonstrate how to enable multi-touch capabilities on all visualizations written with the popular prefuse visualization toolkit. ACM Classification: H5.2 [Information interfaces and presentation]: User Interfaces—Graphical user interfaces, interaction styles. General terms: virtual mouse, multi-touch, information visual-

Information exploration processes are often conducted in teams of experts, family members, or colleagues. These teams have to retrieve information from different sources, verify it, and finally compare and discuss their findings to find consensus. Today, support for these collaborative processes is limited and users often end up sharing either a single PC with one user taking control or using separate workstations, where support for tight collaboration is limited. In this paper, we present collaborative information linking which visually connects information across private and shared application windows to bridge knowledge gaps between users. We present the technical infrastructure for multi-user interaction and personalized meta-visualizations on large multi-projector displays, and demonstrate how personalized visual links connect information across existing applications modified in a minimally invasive manner. An observational experiment showed that information linking helps individuals to deal with large display space and teams to switch between individual information retrieval and joint verification and discussion. Keywords: Single-display groupware, collaborative information work, information linking