We present the use of desktop assistants in the context of web surfing and show how such a tool may be used to support actitivites in both cooperative and personal surfing. By cooperative surfing we mean surfing by a community of users who choose to cooperatively and asynchronously build up knowledge structures relevant to their group. Specifically, we describe the design of an assistant called Vistabar, which lives on the Windows desktop and operates on the currently active web browser. Vistabar instances working for individual users support the authoring of annotations and shared bookmark hierarchies, and work with community interest profiles to make findings highly available. Thus, they support a form of community memory. Vistabar also serves as a form of personal memory by indexing pages the user sees to assist in recall. We present rationale for the assistant's design, show some roles it could play to support surfing and discuss implementation strategies and ongoing extensions.