The user list of this system goes back to 2002 when the radio information was part of the now defunct FindAnISP.com.
The database contained about 15,000 “accounts” where the person submitted a registration request, but then never logged in to the system. In theory, purging those records should have no effect on anyone, other than allowing that email address to be reused for the Streaming Radio Guide, which is also unlikely.
So in case I did something wrong and suddenly your account has vanished, this would be why.