How'd I find out?
I got this email yesterday from my A/R company, icontact:
After consulting with our Deliverability Management team, we regretfully have come to the decision that we will no longer be able service your account within iContact. Your account recently sent email to a known spam trap email address. This means that you had an address on your lists that is maintained by a blocklist and has not been legitimately registered with any opt-in services. This occurrence caused one of our sending servers to become blacklisted.
Keep in mind, with this account, we don't buy any traffic or leads. It's all 100% from someone finding the site in google, and entering their info on the squeeze page.
been doing it like this for 6 years now with this site, with no issues till yesterday.