Located in the email header, your email's subject line is, next to your name, the first thing the recipient sees indicating what the message is about. To increase user engagement, your subject line should be short (30 - 40 characters including spaces, or 4-7 words), and include a truthful, accurate description of what your email is about. Effective subject lines are associated with improroved return on investment (ROI). in order to be effective. MyNewsletterBuilder (MNB) has a strict anti-spam policy prohibiting you from spoofing your subject line in accordance with the CAN-SPAM Act.