Study: Email Deliverability Still a Challenge, but Content Not Main Culprit

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Contrary to widely held belief, email message content is not a major cause of deliverability challenges for most email marketers, according to the Lyris EmailAdvisor ISP Deliverability Report Card for 1Q07.

Moreover, most of the largest U.S.-based ISPs have the lowest rates of delivering email to the inbox, according to (pdf) Lyris, a subsidiary of J.L. Halsey (via MarketingCharts).

According to the report, “two frequently triggered Spam Assassin rules generated content filter point scores of significance…. The first rule cautions against heavy use of images, which can increase spam scores up to a full point and render poorly in email clients with image blocking enabled. The second problem, sending messages with a ‘From Name’ composed of numbers or symbols rather than an actual name, can also increase the likelihood of the message being flagged as spam and ending up in users’ junk/bulk folders.”

However, “it’s an oversimplification to place blame primarily on content filters when a campaign has poor returns, when in fact most delivery challenges are due to subscriber feedback” - such as complaints by recipients who mark a message as “spam” in their email clients - said Stefan Pollard, Director of Consulting Services at J.L Halsey’s EmailLabs.

Deliverability rates can also be adversely affected by - in addition to individual ISP policies and sender content - the sender’s mailing history, number of complaints the sender receives, data collection practices, use of sender authentication protocols and other reputation factors, Lyris said.

Of the 25 U.S. ISPs tracked by the EmailAdvisor Report Card, several leading providers rank among the top 10 domains with the highest rates of delivery to the junk folder: Gmail (third with 28 percent), Yahoo (fourth with 19 percent), and Hotmail (sixth with 16 percent).

AOL ranked 14th, with a junk delivery rate of only 2.33 percent.

For the study’s top-ten ranked U.S. ISPs, gross deliverability was more than 90 percent in all cases, with average deliverability of 83.8 percent across the sample.

CompuServe had the highest rate of inbox delivery at 88 percent, with the remainder of the top-ten ranked ISPs achieving delivery rates of more than 81 percent.

Among international ISPs, European ISPs performed the best, followed by Australian, Canadian and finally U.S. domains - although the disparities between regions were all within five percentage points.

Methodology: For the period January 1 to March 31, 2007, the Lyris EmailAdvisor service monitored the delivery trajectories of 440,694 production level, permission-based email marketing messages sent from 69 different businesses and nonprofit organizations to multiple accounts at 54 ISP domains in the United States, Canada, Europe, and Australia.