1. A method for predicting a person's preference for an item, comprising: receiving, via an electronic device, identifying information about an item of interest; and by one or more processors: accessing a user profile for a person, wherein the user profile comprises a preference model representing associations between the person's ratings of items and a plurality of item characteristics; accessing a database of characteristic values for a plurality of candidate items; using the identifying information to identify a candidate item that corresponds to the item of interest and retrieve one or more characteristics of the identified candidate item; processing the retrieved characteristics with the user profile to generate a predicted rating for the item of interest for the person by: determining whether the retrieved characteristics of the identified candidate item correspond to one or more indicators of preference in the preference model, and based on whether the retrieved characteristics of the identified candidate item correspond to one or more indicators of preference, generating the predicted rating as a prediction of whether the person is likely to like or dislike the identified candidate item; and causing the electronic device to output the predicted rating to the person.