Done correctly, this once-maligned strategy can be a real boon to your list health.

By Catherine Algeri

Side note: How does an e-mail update work? Similar to an e-mail append, you send a file of hard-bouncing e-mail addresses to a reputable vendor. It will search its permission-based databases for new e-mail addresses linked to your records. Then the vendor will send a “welcome back” message to those e-mail addresses on its server. It will return only those e-mail addresses that are valid and have not opted out of hearing from you at this new e-mail address.