Return Path’s latest Email Blocking and Filtering Report shows that 19.2 percent of email still gets blocked or filtered by the leading ISPs and commercial filtering applications. While that is certainly better than the 20.5 percent during the second half of 2005 — and much better than the 22 percent peak in 2004 — don’t let the modest improvements to inbox reach fool you. Too much of your email is still not reaching your customers, making email deliverability an area needing continued focus.

Consider this: six leading ISPs still blocked more than a third of commercial e-mail for reputable marketers, with one (Excite) blocking more than 50 percent. And the ISP with the lowest incidence of blocking, CompuServe, still blocked nearly 12 percent.

For more detailed ISP delivery information, check out their full report here.