Blocking of Legit E-Mail Still High

One fifth of permission-based emails did not reach the inbox during the first half of 2005, according to a new deliverability study from Return Path.

Twenty-one percent of legitimate email marketing messages were either blocked or filtered into the junk folder. The rate was statistically flat compared with the 2004’s first half, when 22 percent of messages failed to get through.

A close look at the numbers suggests senders owe their delivery problems at least as much to their own practices as to overzealous blocking by ISPs. Blocking rates for individual mailers ranged between one percent and 54 percent.

Of course, some inbox providers are more aggressive with blocking than others. Those with the highest delivery rates for legitimate mail included Mac.com, which filtered or blocked only eight percent, and Earthlink, which blocked 10 percent. At the other end of the spectrum are Gmail (39 percent blocked), MSN (33 percent) and Hotmail (32 percent).

Most deliverability problems can be traced to a handful of root causes, according to George Bilbrey, general manager of Return Path’s delivery assurance program. He said list quality problems and the number of complaints against a sender are two big ones.

“Your practices determine your deliverability,” Bilbrey told ClickZ. “The good news from the study is if you do work to improve your behavior, you can improve your deliverability rates. It’s entirely in your control.”

The study examined 140,000 marketing and “transactional” campaigns sent by Return Path’s clients between January and June of this year.