The latest research report conducted by Jupiter Research finds that the cost to online marketers of permission e-mail messages being erroneously blocked as spam will sky rocket from $230 million in
2003 to $419 million in 2008. Due to improved ISP efforts and sender authentification systems, Jupiter Research reports the percentage of permission e-mail being erroneously blocked will decline from
17% today to just under 10% in 2008. Total spending on retention and sponsored e-mails will increase during the same period, however, which will account for the continued increase in spending wasted
on e-mail that will fail to make it to consumers' inboxes.