The newsletter unsubscribe rate refers to the percentage of subscribers who choose to opt-out or stop receiving a particular newsletter. This metric is used to measure the effectiveness of a newsletter and the level of engagement from its subscribers. A high unsubscribe rate may indicate that the content or frequency of the newsletter is not meeting the expectations of its audience, while a low rate suggests that the newsletter is successfully retaining its subscribers. Tracking the unsubscribe rate can help businesses and organizations improve their newsletter strategies and tailor their content to better suit their audience’s interests and preferences.