The system and method analyzes activities of users in a recommender system to identify experts. Two types of experts may be identified: authoritative experts and hub experts. An authoritative expert is a user who creates items or documents in a given field that are acted upon by a large number of users within a community who are well connected in the given field. A hub expert is a user who is aware of important items or documents within a given field and uses, works or acts upon items or documents produced by authoritative experts. The system and method also identifies authoritative items (e.g., documents). An authoritative item or document is one which has been acted upon by a large number of users within a community who are well connected in the given field (i.e., hub experts).