The content of your email — whether the copy itself or the offer you’re promoting — should be something the email recipient actually wants to receive. And you would know what they want to receive if you’ve spent time collecting lead intelligence, segmenting your email lists based on that intelligence, and mapping the appropriate content to each segment of your list.
What some email marketers do, however, is email blast a 10% off coupon for dog food when half of their email list only owns a cat. If the content you’re sending out won’t be helpful to everyone on your current list, slowly back away from the ‘Send’ button, and refine the list to which you’re sending your email.
If you want me to stay subscribed, keep it relevant to my interests!