Shoppers are opening those promotional emails

If it seems as if your inbox is getting flooded with more promotional emails, it's not your imagination.

According to new research by Experian Marketing Services, the amount of email sent by marketers during the third quarter increased 24.8 percent compared with the same period last year. That includes a 27.6 percent increase among retailers.

But before you start groaning, consider this: You may be contributing to the influx.

Retail emails displayed on an iPhone.
Adam Jeffery | CNBC

Despite the fact that retailers, travel companies and other consumer-facing brands are sending out more emails, the percentage of people who opened those messages reached 17.5 percent. That's up from 16.7 percent the prior year.

What's more, although the number of emails that resulted in transactions and total revenue per email declined, 37 percent of brands posted significant year-over-year increases in these metrics, according to Experian.

"Scale is often a marketer's Achilles' heel when it comes to email — increase your volume and expect to see a decrease in engagement and effectiveness," said Spencer Kollas, a vice president at Experian. "When we see the opposite — and our latest data shows that we're seeing a shift — it's a sign of ... leveraging data to drive smarter marketing decisions."

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This inundation of email has continued into the holidays, including a 68 percent increase in messages from travel companies, and a 36.4 percent increase from retailers, according to Experian. However, only retailers have been able to match last year's transaction rates.

Experian attributed that trend to retailers' ability to "better segment and target messages" so they're relevant to individual shoppers. That said, the number of emails that can be directly linked to a transaction remains minuscule at 0.05 percent.

Experian's findings aren't the first sign that retailers are making strides in using data to better connect with consumers. Last month, data from Adobe's Digital Index found an increase in traffic from email marketing was contributing to the rise in online sales.

"People have gotten very used to receiving those promotional emails in the very early hours," Adobe's Tamara Gaffney said.