A method for facilitating collection and display of information related to data usage by a plurality of mobile devices is disclosed. The method involves receiving first quantity information and sending a first identifier associated with the plurality of mobile devices and first activity-related information including the first quantity information to a server. The method also involves receiving group activity-related information associated with the plurality of mobile devices, the group activity-related information derived at least in part from second activity-related information including second quantity information, and producing signals for causing a display to display information derived from the group activity-related information. A method of associating a plurality of mobile devices in a group is also disclosed. Systems and computer-readable media for facilitating collection and display of information related to data usage by a plurality of mobile devices and for associating a plurality of mobile devices in a group are also disclosed.