DM News: Comparing 'Apples and Oranges' in Evaluating E-Mail Delivery Rates

JupiterResearch noticed that different email service providers (ESPs) use different ways of calculating their deliverability rates. With ESPs touting the rate emails sent by them get to their intended readers' email in-boxes, the measure has become a major criterion used by marketers to select a partner. But some ESPs, it turns out, aren't counting all of the bounces, dropping from their figures the "hard bounces" that usually occur when an email account no longer exists.

Jupiter found that 61 percent of ESPs excluded the hard bounces, although major email firms Digital Impact, @Once, Skylist and ExactTarget were not among them. Jupiter estimates that blocked emails cost businesses about a quarter billion dollars in 2003.