A system and method of predicting a user's rating of a new item in a collaborative filtering system in which an initial set of correlation coefficients for the intended users is used to bootstrap the system is described. The users are members of a predetermined organization and the initial correlation coefficient for each pair of users is based on the organizational relationship between the users. Prior organizational relationship information pertaining to the strength of ties, such as a formal organization chart and social network maps built using interviews or deduced from observed (online and/or offline) interaction patterns between potential users, is used to bootstrap the filtering system. Correlation coefficients can be updated as users rate or rerate items in the system.