YouTube videos appear to have long shelf lives, while the opposite is true for Facebook posts. As for emails? Recent data from MailerMailer suggests that opens peak at one hour post-delivery (11.1% of an email’s total opens), falling off quickly during each following hour. At the 6-hour post-delivery mark, the average email is getting 4.5% of its total opens. On a cumulative basis, 51.8% of an email’s opens have occurred by that time.
The data is based on a study of 1.4 billion opt-in messages sent globally during 2012.
Further results indicate that roughly three-quarters of all opens have occurred by the 18-hour post-delivery mark, with the half-life of an email generally being around 2 weeks in total.
How do those figures compare with other similar analyses? A study released last year by GetReponse suggested that a much greater proportion (23.6%) of opens occur in the first hour post-delivery, with an additional 9.5% occurring in the second hour. However, that study was limited to US accounts in Q1, and appeared also to be restricted to emails sent by retailers. (The MailerMailer study took into account 35 industries, while also analyzing global email open behavior throughout 2012.)
More recent data from Experian appears much closer to the MailerMailer results. Experian found that on average, at different points throughout 2012, around 76-78% of total opens occurred in the first 24 hours post-delivery. (MailerMailer’s figure for cumulative opens after 24 hours is 78.9%.)
One additional point made by Experian in that study: the percentage of email opens occurring in the first 24 hours post-delivery appears to be on the increase. The researchers attribute that to the growing share of emails opened on mobile devices – with the vast majority of smartphone owners of all ages now claiming to read emails on their devices.
A detailed analysis of email open and click rates by hour scheduled (US accounts only) can be found here.