A new study by Retention Science shows a 2.6% increase in marketing email open rates when the person’s first name is in the subject line.
Here’s one you can definitely use. Retention Science says the ultimate subject line is 6 to 10 words.
Five or less came in with the second highest open rate and everything starts sinking after 10. Bad news is that most of the emails (52%) they studied had subject likes in the 11-15 range.