MailerMailer's latest Email Marketing Metrics Report (pdf) takes a look at open and clickthrough rates, the best days of the week to send emails and how personalisation and subject lines can affect open rates.
It finds that emails with subject lines of 35 characters or less are 28% more likely to be opened, and that open rates have declined overall so far this year.
Other highlights include:
Open rates declined to 16.11% in the first six months of 2007, down 3% from the same period last year - something the report blames on the increased use of email programs that don't automatically download images.
These have remained more or less constant, at 3.18%, compared to 3.28% a year ago. They were highest for banking/finance (6.52%) and retail (6.3%), while the entertainment industry had the lowest click rates(1.29%).
Open/click rates by day
Early in the week is best, according to the survey. Emails sent on Mondays achieved the highest open and click rates, followed by Tuesdays.
Using personalised subject lines increased open and click rates - average rates were 18% and 5.02% respectively, compared with 15.86% and 2.09% for emails without personalisation.
MailerMailer looked at around 270m million opt-in email newsletters and campaigns sent by over 3,000 of its customers for the report.
Email Marketing Platforms Buyer's Guide 2007