Battle of the Inbox: Subject Line Trends That Win Readership

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If the inbox is a battlefield your email subject line is at the front, openly fighting with your competitors’ messages to achieve the glorious victory of getting read. Studies suggest that 35% of subscribers read messages based on subject lines alone, and they take just a fraction of a second to decide each message’s fate. If you’re not armed with a captivating subject line, prepare to see your message lose—ignored or deleted.

Your best line of defense is a well-crafted, optimized email subject line that’s tailored to your audience with the right keywords to drive engagement.

Return Path analyzed more than 600,000 messages to determine the top subject line performance trends across multiple industries over a 60-day period. By comparing a message’s read rate against the sending domain’s historical average, we were able to see which subjects created a boost in readership, giving us insight into what works—and what doesn’t—in the battle for subscribers’ attention.

Category: Kids and babies
When it comes to engaging a new parent, our results suggest that your best bet is to take a content-based approach. Messages that focused primarily on information about child development and growth had much higher read rates than any others in the category. Popular subject lines in this category include:

  • “Caring for Baby’s Skin” (Parents.com)
  • “Month 7: 5 signs your baby’s ready to talk” (Similac.com)
  • “Your baby’s poo: a visual guide” (BabyCenter.com)

Past the infant stage, parents’ concerns seem to shift to saving a few bucks. Subject lines about products for older children promoting percentage-based savings performed well. Read rates increased even more when brand names were paired with savings, like these top-performers:

  • “Handpicked Savings for You! 20% OFF ALL Despicable Me Board Games” (Toys’R’Us)
  • “Check out the Avengers: Age of Ultron Movie Toys & Gifts, now available at Toys’R’Us” (Toys’R’Us)

It may be surprising that “urgent” subject lines did not perform as well. Those including “last chance,” “ends tonight,” or the way-past-bedtime “midnight” had much lower read rates than subject lines promoting sales with no end dates. Maybe one more urgent demand for their attention isn’t what parents want.

So if you want to engage parents, it might be a good idea to stay away from weak performers like these:

  • “Last Chance! Your Free $ ENDS TONIGHT!”
  • “Last chance to save an EXTRA 20% on everything”

Category: Sporting goods
From fishing to golf, from protection to performance – consumers love gear. Our analysis indicated, regardless of sport or function, consumers were more likely to read messages with subject lines featuring the word “gear.” Read rates were even higher when retailers mentioned “team gear,” as in these examples:

  • “NFL Team Gear + Shoe and Bag Deals End Tonight at Midnight!” (Bowling.com)
  • “Customize Your Team Gear with Worldwide!” (WWsport.com)

If subject lines are any indicator, the world’s favorite sport is golf. Golf messages dominated the sporting goods category with more subject lines than any other. So what makes golfers more likely to read their email? Along with the majority of the readers in the sports category, they prefer percentage-based discounts, name brands, and subject lines aimed at improving their game:

  • “CS2 Golf Putting Trainer – Putt Like A Tour Pro – Free Shipping” (InTheHoleGolf.com)
  • “Dress like the pros with Under Armour golf” (Academy.com)

What don’t they like? Let’s just say golf is a patient sport, so don’t try to rush these readers. Messages of urgency and “last chance” deadlines underperformed others in this category.

Based on our analysis it’s clear that in addition to their pets, these subscribers love a bargain. Messages with subject lines offering discounts often experienced a lift in read rates over others. However, consumers want to know what they’re saving on, so consider optimizing your subject line by calling out brand names, especially when it comes to pet food, like these examples:

  • “Save on Tetra Pond Foods at PetSolutions!” (PetSolutions.com)
  • “$5 Off Any Size Bag of ANY Iams Dog Food at Pet Supermarket” (PetSupermarket.com)

In the age-old debate of cats versus dogs, there is a clear winner – at least as far as read rates are concerned. Subscribers were much more likely to read messages with subject lines about dogs. From treats to feeders to toys, lovers of man’s best friend were much more enthusiastic about promotional messages than other types of pet owners were, which should leave us all thinking like this gem:

  • “Oh. My. Dog. #omd” (TeddyTheDog.com)

There’s no magic strategy
Even though some industries are seeing results with these trends, the only real way to know what works best for your brand and your audience is to test. Pick a sample group to send to and change one interchangeable variable within the message, like switching the word “save” with “discount,” and see which subject line is read more. By determining the words, length, and offers your subscribers respond best to, you can optimize all of your subject lines to increase read rates.

This post originally appeared as a byline on Total Retail.



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