—Recently researchers have argued that the prevailing view of Web search, as a solitary activity, is flawed: that, in reality, Web search can be an inherently collaborative task. In this paper we describe and evaluate an approach to collaborative Web search that seeks to enhance mainstream search engines by harnessing the past search experiences of communities of likeminded searchers in order to adapt the result-lists of traditional search engines so that they reflect the niche interests of community members.