The text discusses the importance of including a "list-unsubscribe header" in marketing emails, which allows recipients to easily unsubscribe from mailing lists without having to search for an unsubscribe link. This practice is required by anti-spam laws and helps establish trust with subscribers, leading to cleaner mail lists, lower spam complaints, and compliance with inbox provider rules. The text explains two types of list-unsubscribe headers: "List-Unsubscribe" which specifies a URL or email address for the recipient to click on to unsubscribe, and "List-Unsubscribe-Post" which indicates that one-click functionality via POST request is supported. Gmail and Yahoo are requiring list-unsubscribe headers starting in 2024, and some email services like Postmark automatically include them in their emails.