Pointing the way

Collaborative filtering is based on the premise that people looking for information should be able to make use of what others have already found and evaluated. Current collaborative filtoing systems provide tools for readers to filter documents based on aggregated ratings over a changing group of readers. Motivated by the results of a study of information sharing, we describe a different type of collaborative filtering system in which people who find interesting documents actively send "pointers" to those documents to their colleagues. A "pointer" contains a hypertext link to the source document as well as contextual information to help the recipient determine the interest and relevance of the document prior to accessing it. Preliminary data suggest that people are using the system in anticipated and unanticipated ways, as well as creating information "digests".