These e-mails reached only 79.3% of inboxes during the first half of 2009, according to the company's "Deliverability Benchmark Report." Of the undelivered e-mail, 3.3% is routed to a “junk” or “bulk” e-mail folder, but 17.4% isn't delivered at all, with no hard bounce message or other notification of non-delivery, the company said.
While such personal e-mail accounts as Gmail, Hotmail and Comcast screen e-mail rigorously, marketers face an even tougher time reaching business e-mail addresses that often are protected by layers of e-mail monitoring. On average, 27.6% of commercial e-mails sent to business addresses don't reach the inbox.
Return Path's study monitored data from its Mailbox Monitor service, tracking delivery, blocking and filtering rates for more than 500,000 e-mail campaigns from January to June 2009.