Sender Score

Return Path provides a free service that distributes publicly-available scores for every IP address sending outgoing mail. These scores are determined with the use of an algorithm that returns an overall number between one and one hundred, with 100 being a perfect rating. This is no small task, as there are in excess of over 60 million email users and/or addresses currently in use through mega-ISPs like AT&T, Verizon, and Comcast. For all email marketers, it is entirely possible for the scores to fluctuate from time to time based on recipient’s responses, like unsubscribes, reports of spam, etc.  A Sender score is usually the first metric that most IPs include in their filtering mechanisms in order to decide whether to deliver a message or not.