Email spammers know exactly what they’re trying to get the reader to do. It’s not an esoteric goal, like giving the reader a better understanding of product offerings. How the hell can you measure success with that goal? Spammers want an email open so they can infect you with malware. Or they want a click to collect your banking information.

Approach your email marketing goals with the same precision. Identify the goal of the email, and draft your call-to-action accordingly — to achieve that goal.

via blog.hubspot.com