A portable electronic device displays concurrently a first predefined scrollable area and a second predefined scrollable area distinct from the first predefined scrollable area. The first predefined scrollable area includes a plurality of graphical objects and is configured to scroll in a first direction. Each of the plurality of graphical objects represents a respective set of content items. The second predefined scrollable area includes a list of content items and is configured to scroll in a second direction that is orthogonal to the first direction. The device detects a gesture that corresponds to selection of a first graphical object of the plurality of graphical objects in the first predefined scrollable area; and, in response to detecting the gesture, plays respective portions of one or more content items in the set of content items that correspond to the selected first graphical object.