A method of selecting content items is performed by an electronic device having one or more processors and memory. The memory stores one or more programs for execution by the one or more processors. The method includes providing a first content item to a first user. The first content item is selected from a plurality of available content items, such as audio tracks or videos. The first user provides feedback relating to the first content item, and the feedback is used to adjust content item selection criteria for a second user distinct from the first user. The method includes receiving a request for a content item from the second user and selecting a content item from the plurality of available content items for the second user according to the adjusted content item selection criteria. The selected content item is then provided to the second user.