What key metric is used to track the performance of online newsletters?

The open rate is a crucial metric for tracking the performance of online newsletters as it measures the percentage of recipients who open the email. This metric provides insight into how compelling the subject line and preview text are, as well as the overall relevance of the content to the audience. A higher open rate typically indicates that the newsletter is successfully grabbing the attention of its audience, which is essential for engagement and further actions.

While other metrics like the click-through rate, conversion rate, and engagement rate are important for other aspects of email performance, the open rate specifically focuses on initial engagement with the content itself, making it a primary indicator of how well the newsletter resonates with its recipients right from the start.