I have about 1000 people who answered a survey about 10 years ago that were interested in the product I was going to develop. They indicated they'd like me to send them an email when the beta release was out.
Obviously it took a long time (10 years), but I finally am in beta and want to send them that email.
However, I don't want to send them all out without quickly getting rid of the obviously bad email addresses. After 10 years, I expect 80% of the emails will have changed and will bounce back to me. My ISP service would not appreciate that many bounces from one mailing.
So is there a fast and simple way to pre-check the email addresses prior to sending them?