1. A method, comprising: identifying a first user having stored in a database a set of first bookmarks associated with a topic of interest; determining a level of relatedness of a second user to the first user by comparing a first number of overlapping bookmarks that were stored in the database by the second user and that overlap the set of first bookmarks; determining a level of value of the second user to the first user by comparing a second number of related nonoverlapping bookmarks that were stored in the database by the second user, that relate to the topic of interest, and that do not overlap the set of first bookmarks; and presenting at least a portion of the related nonoverlapping bookmarks to the first user.