For three months, mysterious telephone numbers have been appearing on the Craigslist classified ad site which, when called, play recordings which sound much like shortwave numbers stations used by certain governments to communicate with intelligence agents in the field who are unreachable by other means. Now the secret behind these phone numbers stations has been revealed.

The numbers stations, placed on Voice over Internet Protocol (VoIP) telephone numbers, were created by several people who attended the Los Angeles 2600 meeting in May of this year, apparently just for the hell of it.