Dive Brief:

• The Netflix hit show “Stranger Things," which is set to roll out season two today, helped marketers boost Halloween-themed email engagement by 74% when the show's title was mentioned in subject lines, per a Mailjet study cited by Netimperative. In the U.K., however, engagement increased only 10% when the show was mentioned in an email subject line.
• The study also found that other seasonal topics like "Halloween" and "pumpkin spice" led to higher email engagement. When mentioning "Halloween" in a subject line, brands can snag a 68% higher open rate in the U.S., but that engagement dropped by 7% among U.K. consumers. Starbucks tested subject lines touting "pumpkin spice" and saw a 90% surge in open rates in the U.S. and a 10% increase in the U.K., per the study.
• "It's easy to assume the success Starbucks sees is testament simply to the quality of the product, but this overlooks the marketing effort behind the scenes. Starbucks has a brand personality that comes through in every email," said Josie Scotchmer, Mailjet's U.K. marketing manager. "As a matter of best practice, tailoring your content in this way and being responsive to what engagement rates are telling you is essential in keeping your brand relevant and appreciated."

Dive Insight:

Halloween is very popular in the U.S., which might explain why the Mailjet study showed smaller jumps in engagement when U.K. brands used the term "Halloween" in email subject lines. At the same time, seasonal topics like pumpkin spice and Stranger Things demonstrates their cross-cultural appeal, pointing to the need for brands to know who their target consumers are in order to optimize email engagement strategies around the fall season.

Several brands have linked themselves to the hit show Stranger Things in recent months ahead of its season two premiere on Oct. 27. Last week, Farmers Insurance launched a digital campaign where users can explore some of the company's strangest insurance claims via a 360-degree experience. Most recently, Sony Pictures and Adidas-owned Reebok debuted a limited-edition sneaker inspired by the show, and Netflix and ride-hailing service Lyft partnered to give customers a creepy themed car ride in select cities.

On top of knowing their target consumers, marketers should A/B test various subject lines to gauge their audience's interests and behaviors, as Mailjet shows that these subject lines can have a significant impact on email engagement. In a separate study, Return Path found that the use of emojis in subject lines could trigger higher response rates than traditional text-based ones. For example, a campaign for Halloween costumes got a 23% percent open rate with the spider emoji in the subject line, but only 14% when the skull icon was used. The novelty of the cartoonish motifs could certainly wear off with overuse, but at the moment, marketers could consider adding a relevant emoji to spice up a plain subject line and tap into seasonal trends like Halloween, especially as digital communication is becoming increasingly visual.