Hi Andrew, #Fred Langa performed an interesting experiment to see just how much of a #problem this is for your legitimate email traffic. His methodology was a #little flawed, but the results were interesting nonetheless. Based on what I read in Fred's article, I think he did a number of things that increased the probability his mail would end up getting filtered; among the most notable is the fact that freetune.com appears to be its own mail exchanger, and that's fine, *except* for the fact that 66.48.80.21 appears to lack a valid in-addr/PTR record. That will hurt deliverability quite a bit. Having a from address that includes "free" is also worth a minimum of a point and a half to folks using the default SpamAssassin rulesets (remember, freetune.com was the domain he used); see: http://spamassassin.rediris.es/tests.html for a list of other tests that may have triggered filtering for his mailing. He also picked an unfortunate Subject: line text, "Hello", since a number of viruses also use subject lines such as "Hello" and some sites filter traffic with that Subject: line (for example, Penn State was doing this -- see: http://live.psu.edu/story/5558 ). I suspect that there were other characteristics to his mail that also ended up tripping content-oriented filters, but I couldn't do more than speculate w/o actually seeing specimens of his mailings. What I find interesting/amusing is that: -- Fred doesn't "get it" that content based filters are a far bigger issue than DNSBLs -- because of the concentration of email accounts, 40% non-delivery may simply be a function of getting blocked by half a dozen of the largest ISPs or a couple of the largest filtering appliance companies (such as Brightmail). -- some of his problem may be OUTBOUND mail back TO HIM that got filtered, rather than mail FROM him getting filtered; his success rate is thus really a joint probability function that depends on TWO messages being successfully delivered (and I bet you that a LOT of people DID just hit reply, regardless of his instructions). Regards, Joe
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