Now that you know a little bit about what a blacklist is and what it’s used for, let’s get into how blacklisting works and how you might find yourself on a blacklist.
First we’ll cover private blacklists, such as McAfee, Hotmail, and blacklists run by prospect IT teams on corporate email servers. These blacklists generally tend to be based on email content and email volume. However, since these blacklists are privately owned and operated, we cannot easily determine what specific element of an email necessarily caused the listing. In cases of private blacklisting, it’s a good idea to double check your email content to make sure it:
- Contains more text than images (check it with this neat tool)
- Includes your physical address as well as an unsubscribe link (as required for CAN-SPAM compliance)
- Isn’t being sent from a general marketing@, sales@, or info@ address
- Is being sent from a domain with SPF and Domainkeys set up
- Doesn’t contain any mentions of FREE, $$, excessive! punctuation!, or “Click here now!” in the subject line (Returnpath has an AWESOME article on spammy words here)
If your email appears to follow all of the above recommendations, you may want to consider how many people you are sending to at once for a particular domain. For example, sending to 1,000 @example.com addresses in an extremely short span of time often triggers servers to block further mail to @example.com addresses, as there aren’t many instances where you would need to send the same email to that many prospects on a single domain. If you are sending legitimate mail to that many prospects at the same company, we recommend reaching out to that receiving server’s administrator to let them know your mail is legitimate and wanted. Additionally, splitting your list into multiple smaller sends can improve your deliverability to these domains, as you aren’t opening too many connections at once to send email.
Next, we’ll take a look at public blacklists. The most common way public blacklists catch unsolicited email is by setting up what’s known as a spamtrap. Spamtraps are email addresses owned by major blacklisting organizations that are specifically designed to catch spammers. These email addresses may seem legitimate, but sending an email to them will cause you to get blacklisted. The problem is, since they look like legitimate email addresses, you aren’t able to easily figure out which email address is the spamtrap.
There are two different types of spamtraps: repurposed spamtraps and pristine spamtraps. A pristine spamtrap is one that has never been owned by anyone else and is set up specifically to catch spammers. This type of email address has never opted into any marketing, so if a sender is emailing to this address, they must be sending unsolicited email. A repurposed spamtrap is one that may have been used previously, but has been converted into being a spamtrap.
Repurposed spamtraps are different in that they may have opted in back when they were owned by a prospect. However, it’s important to note that these addresses typically spend 12-18 months sending back hard bounces to anyone who tries to email them, so legitimate permission-based marketers know to stop sending mail to that address. If someone continues to send mail to that email address after the bounce period is over, that sender is likely sending unsolicited email and can be blacklisted. This is why we recommend sending a permission pass to any prospects who haven’t engaged via email in over a year, as it’s a very high-risk problem for spamtrap hits and thus, blacklisting.
So now that we’ve reviewed a bit about how blacklisting occurs, what happens if you find yourself on a major blacklist? Stay tuned for part 3 of our blacklisting series, “I’m on a blacklist, now what?”