Cloudmark Email Filtering: Silent but Deadly

Why a company you’ve never heard of may be killing your email campaigns before they even get started.

Questline sends and monitors a lot of email for our energy utility clients. By far, we find Cloudmark responsible for more filtering and blocking of that mail than any other reason. But you’ve probably never even heard of them. So today, let’s uncover what Cloudmark does and why they’re so different from your average spam filter.

What is Cloudmark?

Cloudmark is one of the largest providers of anti-spam solutions in the world and protects over 1.6 billion mailboxes. Their technology is used by nearly every major ISP in North America, including Comcast, Time Warner, Cox, Earthlink, AT&T, Sprint, Nextel, and more. Whether you’re sending to a residential audience, small business owners, or even large business customers under corporate domains, your messages are almost guaranteed to be analyzed by Cloudmark.

How does Cloudmark filtering work?

Cloudmark offers many software products and services to mailbox providers. You’ll find their filtering technology at multiple levels of an ISP messaging system. But what makes Cloudmark unique is their innovative use of crowd-sourced spam detection that goes far beyond keyword scanning or IP reputation metrics. Every message that passes through Cloudmark’s system is “fingerprinted” by complex algorithms that analyze the header, body, and attachments. Cloudmark then uses their entire global reputation network to identify fingerprint patterns in messages that have hit spam traps or have been marked by your customers as spam. They then use these patterns to identify other incoming messages and determine if they are delivered, blocked, or sent to the junk folder. And they do all of this in real time. We’ve seen instances where a large marketing campaign was fingerprinted early in the deployment. Before the send could complete, Cloudmark was already sending larger percentages of the mail to junk folders.

The most important thing to remember is that if your messages are marked as spam by customers or you’re using poor list hygiene practices, you will experience deliverability issues at almost all of Cloudmark’s 1.6 billion mailboxes. Yikes!

How can I avoid a Cloudmark fingerprint?

Cloudmark technology is intended to support legitimate senders by promoting email best practices such as:

  • Maintaining consistent branding, sending domains, and domains in call to action links
  • Using feedback loop data to remove customers who mark messages as spam
  • Employing dedicated IPs and avoiding distributing mail across multiple email providers
  • Suppressing inactive customers to increase engagement and eliminate spam traps
  • Avoiding email appends, list rentals, and purchases
  • Following MAAWG Sender Best Communication Practices

Because Cloudmark filtering is largely tied to customer complaints and spam trap hits, use of best practices like these will not only help prevent blocking by Cloudmark but will also help with other reputation-based and engagement-based spam filtering.

Questline deliverability support

Questline’s Engage platform and other products already take care of the technical details required to evade Cloudmark fingerprinting. And our Accounts and Deliverability teams help ensure our clients’ mailing practices exhibit the positive behaviors that Cloudmark and ISPs are watching for. But if you’re sending mail with other providers or managing it all internally, this is an area you’ll want to pay serious attention to.

Contact Questline to find out how we can better help you achieve the highest possible ROI for your campaigns.