ISP whitelisting and complaint feedback loops (FBL) are essential tools used to solve the reputation equation. Whitelists are typically created and maintained by ISPs or third parties, and are lists of IP addresses or domains that are allowed to send mail to a domain. An FBL is a reporting mechanism by which ISPs provide data, including unsubscribes and spam complaints, back to a sender.
While not all ISPs offer whitelisting and/or feedback loops, those that do typically require senders to have explicit opt-in permission from subscribers. The anti-spam community and ISPs use spam complaint rates and spamtrap hits in order to judge a sender’s reputation. Senders receiving high rates of spam complaints, or those who mail to spamtrap addresses (even once) can fall off of an ISP’s whitelist. Therefore, obtaining subscribers’ explicit permission is the only way to ensure that your email campaigns achieve highest deliverability rates from the start. Here is a review of the definitions for the various levels of permission:
No permission (opt-out): Provides an unsubscribe link or checkbox. While such practices are legal per CAN-SPAM and some international anti-spam laws, opt-out (or unsolicited) email typically leads to spam complaints that negatively affect a sender’s reputation. ISPs are often hostile to mailing lists whose addresses were obtained via this process.
Implicit permission: Does not require subscribers to take an ...