measuring, using wearable technology, physiological parameters of a plurality of users of the video repository while the plurality of users watch at least a subset of videos of the video repository;

determining attraction values of the plurality of users to the at least subset of videos using gaze detection technology and based, at least in part, on at least one of: the physiological parameters and facial recognition technology;

forming groups of the plurality of users by maximizing an aggregate function applied to all attraction values between users in each of the groups and all of the videos that the users in each of the groups have watched; and

searching only the subset of videos of the video repository that have been watched by at least one member of a particular group, the particular group corresponding to the particular user, wherein the forming of groups of users that maximize the aggregate of the attraction values for the subset of videos includes constructing a graph that, for all of the users, connects each of the users to each video of the video repository that each of the users has watched and wherein, for all of the users, edges of the graph correspond to the attraction values of the user to each video of the video repository that each of the users has watched.