A clear statement by the user wanting to be removed from a mailing list. Usually done via an unsubscribe button in the mail itself or adjusting settings in a profile. Most countries have legislation set in place that obligates the sender to give a clear chance for the user to stop getting further commercial emails.
About the Author: Chad Klingensmith
Chad is a Sr. SEO Strategist for Rio SEO. He has over 10 years of experience in the digital marketing vertical. He enjoys researching and applying cutting edge marketing strategies to help clients achieve optimal online visibility.