A legitimate message mistakenly rejected or filtered as spam, either by an ISP or a recipient’s anti-spam program. The more stringent an anti-spam program, the higher the false-positive rate.

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.