When newsletters get longer, Clover Letter finds that it can be harder to accurately measure audience

Clover Letter, a newsletter targeted to teenage girls, noted a somewhat unexpected challenge of email newsletters: After a strong start with 70 percent open rates, founders Casey Lewis and Liza Darwin found their open rates started to drop after they began including more GIFs and other images. But it wasn’t necessarily that fewer people were opening Clover Letter. When newsletters get longer, email programs often “clip” them, which can cut off the tracking elements newsletter programs such as MailChimp use to calculate open rates.

+ With this in mind, Clover Letter launched an iOS app, also making it easier to share the newsletter on social media and to archive Clover Letter’s original stories (Digiday); Earlier: Our Q&A with Lewis and Darwin on why they believe teenagers will respond to an email newsletter