Spam, blacklisting

We received this email from a client, regarding a single-opt-in newsletter signup form on their site:

Any one person can go and sign someone up to receive our email newsletter. Most of them may be legit but there are lots of spiders and what not that will sign up as well.

Lets say we take this database and prepare an email marketing campaign. You send out an email or many to this list and we discover that we've been blacklisted by several ESP's (yahoo, msn, etc) because their users are marking our emails as spam - maybe they forgot they signed up for it; don't care to continue receiving it, etc. So, the ESP begins blocking ALL of our email from all users on

Well, we contend that we have the right to send to those users because those folks signed up to receive our email. But we have no way to prove that the email address we have is valid and that the user truly wants to receive mail from us. In order to be removed from a blacklist we have to prove that the specific user(s) in question opted in to receive our email. No more are ESP's accepting a single opt-in as proof. We must have explicit proof in order to be removed and allowed to get through their spam filters. In the instance of egregious "spamming" ESP's can submit an inquiry to the Fed Govt and if we're found non-compliant could face penalties and fines.

Are these valid concerns?  I have a feeling that they're overreacting a bit.  We are planning on implementing a double opt-in form, but I was just wondering whether to tell them "yes, you're exactly right" or "that's partly true, but not completely".

Mathew Mathew, 9 years ago

It is certainly true that single opt in can sometimes have false signups, and if that is a concern for your client you should just make their lists on Campaign Monitor double opt-in. I can say from our end though that we are whitelisted with major ISPs, integrated into their feedback loops and monitor blacklists, and the fact that we allow single opt-in lists has not caused us any real issues.

Our signup forms use unique field names to reduce the likelihood of spiders being able to signup. The unfortunate truth is that people can still make spam complaints even when double opted-in.

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