The E.164 format phone number has been around for over 150 years and over this time has provided a ubiquitous means of identification and routing on the PSTN. Experts have been speculating about the demise of the phone number for some time and with the widespread emergence of communication OTTs the general expectation has been that the phone number will soon lose its original functionality as a communication endpoint on the PSTN. Our research suggests, however, that the phone number is not set to go extinct in the medium term but is more likely to evolve into a unique and core element of digital identifying technologies for a wide range of online services, and is thus likely to retain it's significance for at least another decade or so.