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Janet Roberts

As the Email Bounces, Again
By Janet Roberts

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The buzzy news in the email-publishing word once again is full of "F" words -- as in "false-positive" -- and the rising toll many ISPs are taking on your email publishing by bouncing permission-based email that their filters mistake for junk.

A new report just out from Return Path, the email change-of-address service and consulting firm, found the 12 major ISPs wrongly filtered or blocked about 17 percent of messages sent in the first six months of 2003.

The report doesn't say whether the ISPs are making their filters more difficult to navigate or whether marketers and publishers aren't getting the message on how to avoid the filters. If you're not sure whether your messages are getting through, skip to the bottom for some tips.

(False positives are email messages wrongly identified as spam.)

The company's new Assurance Services division reported in its most recent ISP blocking and filtering report that the delivery-failure rate varied among the ISPs, from a low of 4 percent at Yahoo! to a high of 38 percent at

Assurance Services tracked delivery performance by 12 major ISPs for 9,956 email campaigns by 35 clients. The clients seeded their email lists with special addresses that Assurance used to track whether messages were delivered and whether they went to the in-box or a bulk- or pending-mail folder.

You can see how the 12 ISPs compared in a bar chart at the Return Path/Assurance Web site, but in descending rate of false positives, they are, NetZero, CompuServe, AOL, SBC Global,, MSN, Hotmail, AT&T Worldnet, Earthlink, Bellsouth and Yahoo!.

Yahoo!'s 4-percent false positive rate stood out in the study because it actually had the second-highest delivery-failure rate in the previous study, behind only NetZero. So, something's working right there.

Assurance said it picked the 12 ISPs for its study because, taken together, they account for 60 percent of the addresses in a typical business-to-consumer mailing list. Your results might vary, especially if you have a specialized or business audience.

Assurance also said the false-positive rate rose 2 percent, from 15 percent in the fourth quarter of 2002, although my own scant statistical knowledge would say it was 2 percentage points, not 2 percent. Nevertheless, it shows there's still plenty of work to do to stay out of an ISP's spam filters.

What Can You Do?

  • First, verify how well your own messages are going through.
  • Then, test your messages before sending to identify any potential hotspots.

Verifying Delivery

  1. Request detailed delivery reports and read them in detail. Not all list-management services offer them, but the good ones do. Insist on them especially if you pay for your list-hosting. At minimum, read the final report issued after your mailing has been completed. A mid-mailing report will look hairy because it shows temporary problems, but it will shed additional light if you really need to boost your delivery rate.

  2. Track your own performance across major ISPs by opening email accounts with them and adding those email addresses to your mailing list. This is a small-scale version of what Assurance Services does for its clients.

  3. Assurances Services was Assurance Systems until after Return Path bought the company in June 2003 and added it to a burgeoning family of email services under the Return Path name.

    You can test the addresses two ways: Segment your main list so that the mailing goes only to your test addresses. Or, send your list as usual and monitor the addresses after the mailing finishes to see where messages went.

  4. See whether your IP address, or the one your list host uses to send your mailings, is on a blacklist. Type the IP address, typically an 8- to 12-digit number, into the blank space marked "Spam Database Lookup" at This runs your IP address past a long list of blocklists and shows you which lists you're on, if any. You can also use OpenRBL to test your IP address.

Identifying Potential Hot Spots

Previous Ezine-Tips have listed ways to check whether your email newsletters or campaign messages are likely to trigger blocks or filters, but we'll run them again because this is such an important issue:

  • Watch out for obvious blunders.
    Never use "free" in the subject line. This was the first term anti-spammers seized on to build blocklists. Use a real name -- yours, your ezine name or your company -- in the "from" line if your list-hosting software allows it. Don't use all-capital letters in a single line. Put your ezine name in the subject line. Avoid excessive exclamation points and funky punctuation -- adding a symbol to a potentially sensitive word. That doesn't fool the filters anymore.

  • Test your ad or newsletter copy in a content checker before mailing.
    Several content checkers are out there in the wild, but I like the one devised by Lyris, which designs list- management software and hosts lists. You don't have to be a Lyris client to use it, and you won't get spammed if you do.

If you're a real belt-and-suspenders kind of person, run your copy through a content checker and send it to your test list first before sending to your main list. This double-barreled checking system won't eliminate bouncing and filtering, but it should reduce it.

Ezine-Tips for August 12, 2003

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