Emailing new prospects, educate them, don't sell to them. Give offers to existing customers is my takeaway from this new study. Yes Lifecycle Marketing (a provider of multi-channel marketing services provider) analyzed nearly 8 billion emails to determine if subject line offers in emails work. Findings: 30% of all emails analyzed had an offer in the subject-line Open rates for emails without an offer were on an average 28% higher Exception - emails to customers (loyalty marketing). According to Media Post Research - "Emails with offers related to loyalty boasted a 9% higher open rate, 20% higher click rate, and 12% higher click-to-open rate compared to campaigns with no offers"