Disclosed are methods, systems, apparatus, devices, products, and other implementations, including a method that includes monitoring a plurality of messages from a plurality of mobile devices, each of at least some of the plurality of messages including at least one identifier of at least one content data record, from a plurality of content data records, stored at least on a sending device sending the respective message, and data representative of number of times the at least one content data record was used on the respective sending device. The method also includes determining popularity metrics for one or more content data records from the plurality of content data records based on the data included in each of the at least some of the plurality of messages representative of the number of times the respective at least one content data record was used on the respective sending device.