I am frequently asked about the expected open rate for email messages. According to the Technology Marketing Benchmark Survey, published by Marketing Sherpa, the average open rate for email campaigns in 2008 was reported to be 22%. Overall the open rate has been declining steadily over the past five years from 39% in 2004.

Email open rates are calculated by placing “beacon” images into HTML messages, with the source of those images on a remote web server. When these images are loaded into the recipient’s email reader and are requested from the remote web server, the “open” is registered.

The decline in email open rates may be more attributed towards a greater number of email clients blocking images, rather than acceptance of email.

This information as well as many more useful marketing benchmarks can be found in Marketing Sherpa’s 2008-2009 Technology Marketing Benchmark Survey.