A device includes a communication unit including at least one of a wireless communication module and a wired communication module. The device also includes a controller configured to access, based on communications received through the communication unit, a plurality of identifiers which each mark a manipulation of content performed by an electronic device. The plurality of identifiers mark manipulations of the content performed by different electronic devices. The controller also is configured to facilitate output, on an output unit, of a representation of the plurality of identifiers. The output unit is separate from the different electronic devices that performed the manipulations of the content marked by the plurality of identifiers.