Gross deliverability rates of permission-based email marketing messages for European internet and email service providers were better than for U.S. ISPs and ESPs in the first quarter of the year, according to J.L. Halsey subsidiary and email marketing solutions provider Lyris Technologies. European ISPs achieved an impressive 94 percent, while U.S. ISPs' average gross deliverability went down 6 percentage points from the previous quarter, to 86 percent.

U.S. ISPs and ESPs fared even worse in terms of inbox delivery - 82 percent, compared with European inbox delivery rates of 94 percent. The incidence of false-positive spam filtering is also higher in the U.S., with 7.7 percent of valid messages getting blocked, compared with 3.5 percent in Europe.

Lyris also found that users with email addresses with one of the top 10 U.S. providers were 38 percent more likely to receive their opt-in email in their inbox than those who used one of the bottom 10 providers: 97.4 versus 59.4 percent. At 97.1 percent, inbox deliverability for the top 10 European providers was comparable to that of U.S. providers.

False-positive filtering remains high at Gmail and Hotmail. Gmail had reduced its false-positive filtering over the course of 2005, but rates underwent a dramatic increase in Q1, with 44 percent of emails filtered. Hotmail's false positive filtering also increased, from 15.7 in Q4 to 23.4 in Q1.

The term "gross deliverability" refers to the total number of messages delivered to the email inbox and bulk folders, combined, divided by the total number of messages sent. The term "inbox deliverability" refers to the total number of messages delivered specifically to the inbox, divided by the total number of messages sent.

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Lyris: Email Delivery Rates Increase