Study: Email Deliverability Dropped Precipitously In Second Half of 2011 For First Time

Fewer emails — only 76.5% — landed in inboxes worldwide in the second half of 2011, a significant decline from the typical 80% rate that has held for the past 3 years, according to a new study released by deliverability firm Return Path. This is the first time the company has seen a major decline.

The results indicate that 1 in 4 emails were being delivered to the spam folder or being blocked during that time period, as compared to the normal 1 in 5 rate. Spam folder placement came in at 8.4%, and emails being blocked by ISP-level filters came in at 15.1%, or 20% worse than the first half of last year.

North America, especially, saw a significant (8%) drop, with inbox placement rates falling to 79%, from 86.5% in the first half of 2011. Spam folder placement rose 19% to 7.4% during the time period, and missing or blocked email increased 38%, to 13.3%.

The company also collected some interesting Gmail-specific information. Ninety-three percent of Gmail subscribers now have priority inbox enabled, up 15% from the previous study. Also, Gmail inbox placement rates declined to 79%, with 21% being delivered to the spam folder.

Return Path execs believe that ISPs are raising the bar on reputation metrics, leveraging data like engagement, subscriber panel complaint data and trusted subscriber data, making reaching the inbox more difficult for marketers. The research also concluded that consumers are overloaded with marketing messages, especially during the holiday shopping period, and are therefore more likely to report them as spam instead of unsubscribing.

For the study, Return Path analyzed more than 1.1 million campaigns and data from 142 ISPs worldwide, from July to December 2011.