Lyris: Hotmail, Gmail Filter More Permission E-Mails

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Though delivery rates for permission-based e-mails rose for the third straight quarter, MSN's Hotmail and Google's Gmail filtered out more legitimate e-mails, according to a new study from e-mail delivery firm Lyris Technologies.

Hotmail's rate of "false positive filtering" -- filtering permission e-mails to junk boxes and other folders -- jumped from 5.6 percent in the second quarter of 2005 to 9.4 percent in the third quarter, according to Lyris' quarterly Email Deliverability report, provided exclusively to DM News.

Hotmail's introduction of Sender ID in the past quarter could have caused the spike in delivery problems to that ISP, said Shannon Coulter, senior marketing manager for Lyris, Berkeley, CA. With Sender ID, Hotmail sends e-mail in which the sender cannot be verified to customers' junk e-mail boxes.

Gmail's false positive filtering rate rose from 4.1 percent to 7.17 percent in the third quarter.

"Gmail is still relatively new to the space," Coulter said. "They are fine-tuning it, [and] they will figure it out."

ISP Concentric ( had the highest jump in false positive filtering in the quarter, rising 42 percent. Coulter did not know why Concentric's rate rose so steeply but noted that the ISP is an aberration in what is happening in the industry overall.

Lyris found that inbox delivery rates are improving across ISPs. Eighty-nine percent of opt-in e-mails were delivered by U.S. ISPs, up 4 percentage points from the second quarter.

"It is encouraging," she said. "If you read the literature, the industry sounds pretty embattled as a medium; [but] the marketers who are employing good sending practices, their delivery rates are high."

ISPs with the best delivery rates in the third quarter included PeoplePC, Mailblocks, Gmail, Yahoo, SBC Global and RoadRunner.

Coulter said the rise in deliverability over the past three quarters could be related to Hotmail's implementation of Sender ID, meant to notify Hotmail users that e-mails in their inboxes are legitimate.

"It made a lot of ethical senders get their act together and do a couple of things to get their mail through to Hotmail," she said. "The overall result might be improved deliverability across the board." In addition, ISPs could have changed the way they process e-mails, and senders are "getting more savvy about setting things up so their e-mails get through."

Christine Blank covers online marketing and advertising, including e-mail marketing and paid search, for DM News and To keep up with the latest developments in these areas, subscribe to our daily and weekly e-mail newsletters by visiting


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