Return Path on Content Filtering

Return Path have an interesting post up about content filtering. I like the model of 3 different kinds of filters, in fact it’s one I’ve been using with clients for over 18 months. Spamfiltering isn’t really about one number or one filter result, it’s a complex interaction of lots of different heuristics designed to answer the question: do recipients want this kind of mail?

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Filters and windmills

A colleague of mine was dealing with a client who is experiencing some difficulty delivering to the bulk folder. Said client spent much of a one hour phone call repeating “This is not how a free society works!!”
After the call my colleague commented, “I refuse to get ranty about filter systems.”
I know that filters, and the people who write and maintain them, are a frequent scapegoat for senders. The filters are always the problem, not anything the senders do.
Now, I’ll be the last person who will claim spam filters are perfect, they’re not. Filters sometimes do unexpected things, sometimes they do boneheaded things, sometimes they are broken.
We can’t forget, though, that filters perform a vital role in protecting users from malicious emails. Phishing emails, scams, fake products, viruses are a constant threat. Many end users don’t need to worry about this because filters are so good. But an unfiltered account can get thousands of scams and spams a day (ask me how I know).
Most of us in the delivery space can tell when a filter is working as intended and when there’s an underlying problem. And when the filter is working as intended there’s not a lot of use complaining about them. Ranting about filtering systems often delays a resolution. Senders that focus on what they can control tend to have more success reaching the inbox than those senders that focus on ranting about filtering systems.
Tilting at windmills doesn’t get the mail through.

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Spam works

I got a spam today advertising spamming services that ended with a tagline that can be paraphrased: We managed to spam you, let us spam others on your behalf!
OK, so what they actually said was:

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Content, trigger words and subject lines

There’s been quite a bit of traffic on twitter this afternoon about a recent blog post by Hubspot identifying trigger words senders should avoid in an email subject line. A number of email experts are assuring the world that content doesn’t matter and are arguing on twitter and in the post comments that no one will block an email because those words are in the subject line.
As usually, I think everyone else is a little bit right and a little bit wrong.
The words and phrases posted by Hubspot are pulled out of the Spamassassin rule set. Using those words or exact phrases will cause a spam score to go up, sometimes by a little (0.5 points) and sometimes by a lot (3+ points). Most spamassassin installations consider anything with more than 5 points to be spam so a 3 point score for a subject line may cause mail to be filtered.
The folks who are outraged at the blog post, though, don’t seem to have read the article very closely. Hubspot doesn’t actually say that using trigger words will get mail blocked. What they say is a lot more reasonable than that.

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