Abstract: In an embodiment, a data processing method providing an improvement in calls via mobile wireless telecommunications comprises receiving at a server computer, from a calling device comprising a first mobile computing device, mobile call data comprising a media file and an identifier associated with a called device comprising a second mobile computing device; storing the media file at the server computer; transmitting the media file from the server computer to the second mobile computing device using the identifier; using the identifier, initiating a mobile wireless call between the first mobile computing device and the second mobile computing device; and causing displaying the media file on the second mobile computing device in conjunction with indicia indicating that the mobile wireless call is incoming.