One of the reasons e-mail marketing has become so huge is because it’s so darned cheap. Compared to postal mail, e-mail costs just pennies. That means most marketers can achieve a better ROI for just a mediocre e-mail campaign compared to even the most successful direct mail effort.
However, a common complaint about e-mail versus postal mail is visibility. Since most viewers choose not to have their preview pane feature turned on, they must physically open an e-mail before they can view any of its contents.
This “one-step removed” dynamic means that many people never get to see and read a marketing message that would otherwise stand out if it showed up in someone’s postal mail delivery as a postcard or self-mailer promo piece.
In this scenario, the e-mail subject line becomes a huge “gatekeeper” element. What the subject says and how it’s said can make a difference in e-mail open and clickthrough rates. But just how much?
A new E-mail Marketing Metrics Report from MailerMailer, a firm providing e-mail marketing and newsletter services, provides some interesting clues. MailerMailer has been producing these reports since 2003. This report, the tenth one issued, was developed by analyzing a sampling of ~900 million e-mail messages sent through MailerMailer throughout the year 2009.
Among the elements tracked were the words used in e-mail subject lines. MailerMailer found that the most popular terms contained in the subject lines were:
Notice how each of these terms conveys a sense of WIIFM (“what’s in it for me?”) and/or a sense of time sensitivity. Interestingly, despite a prevailing concern that using the word “free” in the subject line risks more spam filtering, MailerMailer found that this term was one of the ten most popular terms used in subject lines during 2009.
And what about subject line length? The report found that shorter subject lines (containing less than 35 characters) outperformed longer ones. That’s generally just four or five words along with the corresponding spaces between them.
And the difference MailerMailer observed was significant: E-mails with shorter subject lines experienced an average open rate of ~17.5%, while those with longer subject lines had an open rate of only ~11.5%.
The same differential was found with clickthrough rates. For the e-mails with shorter subject lines the average clickthrough rate was ~2.7% … versus ~1.6% for e-mails with longer subject lines.
The MailerMailer report concludes that while composing shorter subject lines may be difficult to do (well), going through that exercise is well worth the extra effort. The results from ~900 million e-mails prove it.