A term that refers to the best practices and authentication techniques of mass email communication that improve the likelihood that opt-in email messages are successfully delivered to end recipients instead of being erroneously blocked by ISPs and spam filters.

Building a Highly-targeted Opt in List: When Money Lies Beneath the Lists
Are you successful with your Internet business? Better yet, do you think you are successful with your online business? When most online entrepreneurs are asked with these questions, they often brush it off.