Making Money On-line: The Cost of Free: Subject Lines and Email Deliverability

An enticing subject line is a critical tool in a marketer’s arsenal, driving open rates, engagement in the inbox, and ultimately conversions. A subject line is the first preview a recipient has to the message that awaits them, triggering a split-second decision regarding the fate of a campaign. The question is, will your subject lines drive users to delete, open, or flag your messages as spam?

What’s at Stake?

The risks to a sender’s deliverability and reputation are very real. Spam is increasingly in the eye of the recipient, and good marketers know that relevant content is key to combating user fatigue and maintaining a strong sender reputation. The use of engaging subject lines is a dynamic part of this strategy, but it can tempt otherwise good senders into desperate bids for opens. We’ve all seen such offers in our inboxes:

“$$$ Act Now!”
“FREE FREE FREE”
“Money Inside!”

The reasoning makes sense on the surface: strong deliverability requires an engaged audience regularly opening emails from a brand, and what better way to accomplish this than by convincing users a great deal is only a click away.

But at what point does this language have the opposite effect, getting lost in the shuffle of traditional spam messaging from bad actors trying to reach the same audience? Can using traditionally spammy words like free and money in a subject line sink the performance of a sender otherwise adhering to best practices?

The Results

Using the email performance and deliverability tool, eDataSource, I pulled performance metrics on campaigns sent Q1 2018 (January 1—March 31) for four industries: Apparel: Online Fashion, Financial Institutions, Petcare & Supplies, and Travel Services & Tourism. I then drilled into the performance of only those campaigns that included the word, “free,” in the subject line, as well as those that included the word, “money,” for each industry over the same period.

Subject line data Admittedly, there are countless factors that can account for the inbox rate of a particular campaign beyond subject line, but I strongly believe the data above tells a compelling story for marketers trying to figure out the best way to reach their audiences. Although minimally in some instances, the average performance for campaigns featuring free or money in their subject lines performed lower than the industry averages overall in all four categories.

Interestingly, money seemed to have little impact on Travel Services & Tourism and Petcare & Supplies, whereas free caused a significant drop in performance. Only one category, Financial Institutions, seemed largely immune to this drop-off, with a less than 2 percent performance impact for either keyword. Both keywords triggered a significant performance drop for Apparel: Online Fashion.

What This Tells Us

The standard industry wisdom to avoid using free and similar messaging in subject lines still seems to carry weight. Why? Try assuming the perspective of the recipient. Not only are users inundated with mail on a daily basis from myriad brands, they are conditioned to perceive all unwanted messages as spam, regardless of whether or not they were properly opted in. Today’s email recipients have even gone so far as to create spam-specific email accounts, taking active steps to avoid spam messaging regardless of the offers listed in their subject lines.

So does this mean senders should never use this language? Not necessarily.

It’s Not All Bad

While the deliverability operations team recommends certain words to avoid, the use of a keyword in a subject line is not enough to drive lower deliverability on its own, as demonstrated by financial institutions’ results.

Traditionally, financial institutions are much more susceptible to spoofing or phishing. These are brands that deal directly with the money and finances of their users, and as such, are very attractive to spammers trying to obtain the same information for nefarious purposes. Within this industry space, words like free and money are often unavoidable.

So how do they avoid performance issues? Best practices.

Ensuring proper authentication is in place, that users are being properly opted into campaigns, and that engagement-based segmentation is universally applied. These are still a sender’s best bet for reaching the inbox and are likely more strictly applied in today’s high-stakes email environment.

So, once you’ve applied this to your own sending and have consistently reached the inbox, it’s time to figure out if your subject lines are doing more harm than good. Review your results, analyze the performance of these types of campaigns against the larger whole, and make informed decisions.

Download Email Deliverability: Guide for Modern Marketers to find out how to achieve email deliverability that really delivers.