Recent Posts

Changes at Comcast

I can usually tell when one of the ISPs makes some change to their incoming spam filtering just by my call volume. The past few weeks the ISP in most of my calls has been Comcast. And, what do you know, they have made changes to how they are filtering email.
According to their bounce message, Comcast is using ReturnPath’s proprietary SenderScore product to filter mail. Reports on thresholds vary, but IPs with SenderScores of 70 and below have been blocked with messages similar to:

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Best practices and ISPs

A couple articles came out today talking about ISP requirements and how to find them.
EmailInsider talks about ISP best practices and how merely complying with CAN-SPAM is not enough to get good delivery at the ISPs.
Meanwhile, over at ClickZ, Stefan talks about what the ISPs want from you and how to find the information online.

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Email standards at the email client

The Email Standards Project launched last week. This group is looking to lobby and encourage companies to make their email clients comply with HTML display standards. They are also identifying how different clients display email with HTML. Check out their website, and see what they’re doing.
I do apologize for the light blogging recently. I have a couple big deadlines on my plate. I hope to get back to regular blogging soon.

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Why does everyone tell you to avoid .biz in your emails?

… or Why do spam filters sometimes have some very strange ideas?
It’s been dogma for a long time that if you’re doing email marketing you should avoid using a .biz domain in your mails. Even if your main website was in .biz, you should use something different in your messages, perhaps a website you buy solely for use in email that redirects to your real .biz website. Last year I looked at why that was, and what could be done about it.
One main reason for avoiding it has been resolved (so if you’ve been avoiding using .biz URLs in your mail now might be a good time to re-test that decision). And enough time has gone by that I can share the ugly reasons as to why .biz was considered a sure sign of spam without good reason for so long without upsetting everyone.
The simple reason was SpamAssassin. SpamAssassin is very widely used to filter mail, both in it’s open source version and buried anonymously deep inside countless commercial spam filters and filtering appliances. Not only that, but SpamAssassin is readily available, so most people looking to do pre-mailing content checks or looking at why content-based filters are objecting to a particular email will use SpamAssassin as their model. It’s very widely deployed, and influential far beyond the size of it’s deployed base.
SpamAssassin is a score-based spam filter – it checks an email against hundreds of rules, adds up the scores of each rule that matches and, in typical setups, decides the mail is spam if the total score is five or more. Pretty reasonable, but here are a few of the rules and scores (from the 2006 version of SpamAssassin)

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Useful websites

I’ve been working on a document discussing laws relevant to email delivery and have found some useful websites about laws in different countries.
US Laws from the FTC website.
European Union Laws from the European Law site.
Two documents on United Kingdom Law from the Information Commissioner’s Office and the Data Protection Laws
Canadian Laws from the Industry Canada website.
Australian Laws from the Australian Law website

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News and articles

Things have been insanely busy the last few days so blogging has been light. I do have links to a few news articles though. ClickZ has a report on the benefits they saw when switching to a professional email service provider. ReturnPath talks about changes to the email landscape as we enter the holiday shopping season. Terry Zink talks about how he measures the effectiveness of filters. A commenter on this blog asked about how to improve delivery to AOL, and I should have an answer to that in a few days.

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When to send mail

I had a call with a potential client recently asking me what was the best day to send mail. It’s a question that I did not have a good answer to. Email Insider does have an answer to that question: there is no one day to mail to get the best response.

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Blogroll

I added a few blogs to my blogroll today.
Terry Zink works at Microsoft handling spam blocking issues for one of their platforms. His posts offer insight into how recipient administrators view spam filtering. He has a long, information dense series of posts on email authentication.
E-mail, tech policy, and more is written by John Levine, a general expert on almost everything internet, especially spam and abuse issues. He posts somewhat irregularly about interesting things he sees and hears about spam, abuse, internet law and other things.
Justin Mason’s blog contains information from the primary SpamAssassin developer. Like Terry’s blog, it gives readers some insight into the thought process of people creating filters.
Al Iverson’s blogs have been on my blogroll for a while now. His DNSBL resource contains information about various DNSBL and how they work against a single, well defined mail stream. His spam resource blog provides information about delivery and email marketing from someone who has been in the industry as long as I have.
Email Karma is Matt Verhout’s blog and contains a lot of useful delivery information.
No man is an iland provides practical information on marketing by email. Some of the information is delivery related, a lot more of it is solid marketing information. Mark often points to useful studies and information posted around the net.
MonkeyBrains has always entertaining and informative articles about delivery, email marketing and practical ways to make your email marketing more effective.

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Spamfilters are stupid

Ben over at MailChimp writes about spamfilters that are following links in emails resulting in people being unsubscribed from lists without their knowledge. I strongly suggest clients use a 2 step unsubscribe system, that does not require any passwords or information. The recipient clicks on a link in the email and confirms that they do want to be unsubscribed once they get to the unsubscribe webpage.
Even more concerning for me is the idea that people could be subscribed to emails without their knowledge. For some subset of lists, using confirmed (double) opt-in is the best way to make sure that the sender really has permission from the recipient. Now we have a spam filter that is rendering “click here to opt-in” completely useless. I am sure there are ways to compensate for the stupidity of filters. As usual, though, the spammers are doing things which push more work off onto the end user and the legitimate mailers.

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Greylisting: that which Yahoo does not do

Over the last couple days multiple people have asserted to me that Yahoo is greylisting mail. The fact that Yahoo itself asserts it is not using greylisting as a technique to control mail seems to have no effect on the number of people who believe that Yahoo is greylisting.
Deeply held beliefs by many senders aside, Yahoo is not greylisting. Yahoo is using temporary failures (4xx) as a way to defer and control mail coming into their servers and their users.
I think much of the problem is that the definition of greylisting is not well understood by the people using the term. Greylisting generally refers to a process of refusing email with a 4xx response the first time delivery is attempted and accepting the email at the second delivery attempt. There are a number of ways to greylist, per message, per IP or per from address. The defining feature of greylisting is that the receiving MTA keeps track of the messages (IP or addresss) that it has rejected and allows the mail through the second time the mail is sent.
This technique for handling email is a direct response to some spamming software, particularly software that uses infected Windows machines to send email. The spam software will drop any email in response to a 4xx or 5xx response. Well designed software will retry any email receiving a 4xx response. By rejecting anything on the first attempt with a 4xx, the receiving ISPs can trivially block mail from spambots.
Where does this fit in with what Yahoo is doing? Yahoo is not keeping track of the mail it rejects and is not reliably allowing email through on the second attempt. There are a couple reasons why Yahoo is deferring mail.

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