Data gleaned from a review of all the e-mail acquisition campaigns sent through Return Path's Postmaster Direct Network over the last two years suggests that e-mails with shorter subject lines tend to
get better results. Click-through rates for e-mails with subject lines shorter than 49 characters were 75 percent higher for those with 50 or more. The difference in open rates was less pronounced.
E-mails with subjects comprised of fewer than 49 characters had open rates 12.5 percent higher than those with 50 or more.
--Shankar Gupta
