1. A computer implemented method for determining knowledge and/or expertise, comprising the step of: identifying a target community (or subgroup) of users; observing usage patterns of Web documents and other online assets by said target community (or subgroup) of users; and based upon said observed usage patterns, performing any of the steps of: automatically determining the topic of said Web documents and other online assets; and detecting which of said Web documents and other online assets that are most used and useful to said target community (or subgroup) of users.