A detection device for passengers includes a passenger judgment unit which has a specified load judgment unit and a stability judgment unit, and a plurality of load sensors disposed on supporting parts of a seat of a vehicle. Each time a user selects and plays a media presentation, user events describing actions taken by the user while viewing or listening to the media presentation are collected and provided to a Collaborative Content Track server. A portion of the first original image to be superimposed is determined. This mechanism passes through the base. Upon receipt of the second address, the second node repeats the process.