Systems and methods for managing information about content transmission are disclosed. In some implementations, a first mobile device communicates with a second mobile device, via a short-range radio of the first mobile device, to either send or receive a content item. The first mobile device tags the content item with a tag. The tag identifies the second mobile device. The first mobile device transmits to a server, via an additional radio of the first mobile device, data identifying the content and the second mobile device. The additional radio is different from the short-range radio. The data is transmitted to the server for analyzing short-range radio transmissions between mobile devices.