Back in “the day” Popular Electronics magazine offered certificates for what it called “Short-Wave Monitor Certificate of Registration”. In the 1960’s I wrote in and obtained such a certificate and was assigned “station identification sign” WPE9IYN.
Part of the “deal” was that Popular Electronics also worked with the FCC to reserve the id (without the “PE” in the middle) so that your assigned station identification sign could also become your amateur radio service call sign.
I had intended to work towards an amateur radio license – my uncle and cousin were Hams. I spent some time learning code, but never actually took the exam.
So, after I obtained my license in February, I checked if W9IYN was available, and sure enough, it was. So, I applied for, and obtained that call sign as a “vanity” call sign. So, my Amateur Radio Service call sign is now W9IYN.