Letterman Lessons for Email Subject Lines [Infographic]

After 21 years, David Letterman has announced his retirement. To bid him adieu, email marketing services provider Campaigner has found some interesting correlations between Letterman's opening act and email subject lines.

Shown in the infographic below, Campaigner has identified the top-three tips for email marketers to channel their inner Letterman and set the stage with an attention-grabbing subject, guaranteed to increase overall engagement and ROI.