In some cases, popular illegal forums used by cyber criminals as marketplaces for stolen identities and credit card numbers have been run by hacker turncoats acting as FBI moles. In others, undercover FBI agents posing as "carders" – hackers specialising in ID theft – have themselves taken over the management of crime forums, using the intelligence gathered to put dozens of people behind bars. So ubiquitous has the FBI informant network become that Eric Corley, who publishes the hacker quarterly, 2600, has estimated that 25% of hackers in the US may have been recruited by the federal authorities to be their eyes and ears.