E-mail messages sent on Fridays had the highest average 'open rate' in 2005, according to e-mail service provider ExactTarget, despite the company's findings in 2004 that no particular day of the week was best for e-mail campaigns.
But the change noted in the company's 2005 Response Rate Study (which included data from 4,000+ organisations, 230,000 campaigns, and 2.7 billion messages) is not necessarily an indicator that marketers should begin swapping e-mail marketing campaigns to Fridays, according to Morgan Stewart, director of strategic services for ExactTarget (and author of the study).
Steward warns: "Our 2004 study asserted that there is no such thing as a universal best day to send e-mail, and we still hold that view. The results of our 2005 study show that organisations still must conduct their own tests to determine which day of the week works best for them - although they should consider Friday and Sunday as viable challengers."
Fridays and Sundays best
According to the study, Friday had the highest average open rate for 14 consecutive months (from October 2004 until November 2005). But Sunday actually had the year's highest average click-through rate (the number of times trackable links were clicked in e-mails), followed by Friday. Interestingly, Sunday was a consistently low performer for open rates.
This suggests to the casual observer that, although e-mail messages received on Friday stand a good chance of being opened and followed through on the same day, Sunday is also a popular day for recipients to catch up with the week's e-mail.
Deciding when to send
The ExactTarget study found that e-mail sending activity is generally focused in the middle of the week, with approximately 96% of campaigns and 92% of e-mail volume currently being sent from Monday to Friday.
So, when deciding when to send a timed or automated e-mail communication, companies will need to consider their competition in the recipient's inbox, according to Stewart: "An organisation may have clearly defined competitors in the general marketplace, but its competitors in the inbox can be drastically different. Given that the number of emails sent on Friday is relatively low compared to other weekdays (14.3% of emails are sent on Friday versus 24.5% are sent on Tuesday), the odds of getting the attention of subscribers is higher."
The weekend argument
Indeed, the strong e-mail open results for Friday would seem to support Stewart's argument. The number of e-mails sent over the weekend also is low (ExactTarget says that only 3% are sent on Sunday, and 4.9% are sent on Saturday), which increases the chance that recipients will spend time on e-mail over the weekend.
However, The Wise Marketer notes from its own research that there are good reasons to avoid certain days of week and times of day for e-mail campaigns. For example, in a B2B (business-to-business) environment, many e-mail inboxes reach their inbound message quota by Sunday afternoon because they aren't being downloaded and emptied out each day over the weekend (unlike weekdays) - which can lead to higher return rates for e-mail sent on Sundays (and Saturdays, although to a lesser degree).
However, such issues are not always a problem, according to Stewart: "The relatively high volume of e-mail on the weekend is due to the B2C (business-to-consumer) focus of these campaigns. B2B organisations sending on the weekends may have been rewarded for their unconventional choice of day to send, as their average click-through rates were 25% higher on the weekend."
The study also found a definite seasonal component to e-mail results. While strong open rates generally correlated with strong click through rates, month-to-month click through rates for Sunday varied widely, with the average ranging from 4.9% in June to 8.3% in October.
This variation follows seasonal trends, with low performance in the summer months and best performance in the winter months.
"During the summer months, e-mail recipients are most likely to spend the weekend outdoors, away from their computers," Stewart concluded. "But in the winter months, people spend more time inside, catching up with e-mail and preparing for the week ahead."