1. A method of predicting a user preference of an active user for an unused content item not used by the active user, the method comprising: measuring a first similarity ratio of the active user and a first other user using an overlapping ratio of use of content items commonly used between the active user and the first other user, and measuring a second similarity ratio of the active user and a second other user using the overlapping ratio of use of content items commonly used between the active user and the second other user; generating a recommender list using a gate array or an integrated circuit for the active user based on the measured first and second similarity ratios; and predicting a preference rating of the active user with respect to the unused content item based on a preference rating of the first or second other user included in the recommender list with respect to the unused content item.