feel abstract and informational rather than inviting for social interaction. Consequently, newcomers and occasional visitors to such sites cannot quickly assess who the participants are; what the purpose, tenor, and norms of the space are; which sorts of newcomers are welcomed; and what forms of participation are valued. Thus, users need support for social browsing in such spaces. Ontheflipside,activecontributors to social spaces (such as Web communities) lack the means to present a public face to visitors. Gathering places in the physical world, in contrast, reflect artifacts, patterns, and traces of social presence, activities, and organization.1 They convey the life, character, relationships, and social cues that are important for social interaction and organization. Such social informationandpatternsexistintheelectronicworldbut areburiedinthecontent-centricinformation.(Formore information see the "Social Visualizations" sidebar.) The challenge of creating social browsing ...