Under the CAN-SPAM Act, which took effect in January, the FTC was directed to study the possibility of a national do not email registry.
The agency said it studied three possible registry models, reviewed registry proposals from the industry, consulted with consumer groups, email marketers, ISPs, and others before deciding that such a registry could not be enforced effectively.
"A registry of individual email addresses also suffers from severe security/privacy risks that would likely result in registered addresses receiving more spam because spammers would use such a registry as a directory of valid email addresses," the FTC said. "It ultimately would become the National Do Spam List."
Instead, anti-spam efforts should focus on development of an email authentication system that would prevent spammers from "hiding their tracks and thereby evading Internet service providers' anti-spam filters and law enforcement," the agency advised.
To that end, the FTC will sponsor a Fall 2004 Authentication Summit to help analyze possible authentication systems.