The email service providers coalition is spearheading a lobbying effort to convince the Federal Trade Commission (FTC) to add a sunset provision to the CAN-SPAM Act, allowing the automatic removal of email addresses from suppression files after five years, reports ClickZ. Under the current version of the Act, an address owner must provide "affirmative consent" for the removal. In contrast, telephone numbers on the FTC's do-not-call registry automatically expire in five years.

Unless a similar provision is added to the CAN-SPAM Act, "Email suppression files will continue to grow," warns Trevor Hughes executive director of the group. "In a few years, they will contain hundreds of millions of addresses that never opted out, but that some prior owner opted out."

Because people change email addresses far more often than they do their phone number or street address, email address churn is significantly higher than for other direct marketing channels.