Email filters

What makes the best email filter? There isn’t really a single answer to that question. Different people and different organizations have different tolerances for how false positives versus false negatives. For instance, we’re quite sensitive to false positives here, so we run extremely conservative filtering and don’t block very much at the MTA level. Other people I know are very sensitive to false negatives and run more aggressive filtering and block quite a bit of mail at the MTA level.
For the major ISPs, the people who plan, approve, design and monitor the filters usually want to maximize customer happiness. They want to deliver as much real mail as possible while blocking as much bad mail. Blocking real mail and letting through bad mail both result in unhappy customers and increase the ISP’s costs, either through customer churn or through support calls. And this is a process, filters are not static. ISPs roll out new filters all the time, sometimes they are an improvement and sometimes they’re not. When they’re not, they’re pulled out of production. This works both for positive filters like Return Path and negative filters like blocklists.
Then there is mail filtering that doesn’t have to do with spam. Business filters, for instance, often block non-business mail. Permission of the recipient often isn’t even a factor. Companies don’t often go out of their way to block personal mail, but if personal mail gets blocked (say the vacation plane ticket or the amazon receipt) they don’t often unblock it. But when you think about why a business provides email, it makes perfect sense. The business provides email to further its own business goals. Some personal usage is usually OK, but if someone notices and blocks personal email then it’s unlikely the business will unblock it, even if the employee opted in.
In the case of email filters, the free market does work. Different ISPs filter mail differently. Some people love Gmail’s filters. Other people think Hotmail has the best filtering. There are different standards for filtering, and that makes email stronger and more robust. Consumers have choices in their mail provider and spamfiltering.

Further amendment would be futile
Relevance?

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The answer is 42

I continually run into companies that don’t really have a goal or understanding of their email marketing program. They’ve never really asked questions about how they’re using email or even why email is the right answer. Lots of companies are also diving head first into email marketing or the social media craze without having thought about what their goals are and what they want to happen.
What regularly ends up happening to companies that jump in without a clear goal is they get into a situation where their delivery is bad. Then they read a lot of best practice advice on the net and try to implement all of it. Sometimes that works, but other times it doesn’t. Finally they hire me or another consultant to help them sort out where it all went pear shaped.
My consulting isn’t about rote recitation of common best practices. Instead, I want to know about a client’s business and what they think about email.  The most frequent question I ask clients is: How does email fit into your business? What are your goals for your business? What is your value proposition?
Some of my clients can’t answer these question. They just tell me they want to use email and they don’t know what they’re doing and that’s why they hired me. Well, I can help them successfully send email, but I can’t help them decide what role email plays in their business. Those are the decisions my client needs to make. I can’t set their business goals for them.
When was the last time you actually sat down and just thought about your business goals? I know that sometimes it’s hard to find the time to look at your business and where it’s going. “Think about it? I’m too busy doing it!” But every business person needs to look at their business goals.
Once you’ve thought about your goals, think about your email marketing program. Is email helping you to reach those goals? How?
If you’ve reached your current business goals, what are your next ones? And how does email fit into those goals?
Sure, having an answer is good, but are you actually asking the right question?

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Botnets and viruses and phishing, oh my!

MessageLabs released their monthly report on email threats yesterday. Many media outlets picked up and reported that 41% of spam was from a the Rustock botnet.
Other highlights from the report include:

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Why do ISPs do that?

One of the most common things I hear is “but why does the ISP do it that way?” The generic answer for that question is: because it works for them and meets their needs. Anyone designing a mail system has to implement some sort of spam filtering and will have to accept the potential for lost mail. Even the those recipients who runs no software filtering may lose mail. Their spamfilter is the delete key and sometimes they’ll delete a real mail.
Every mailserver admin, whether managing a MTA for a corporation, an ISP or themselves inevitably looks at the question of false positives and false negatives. Some are more sensitive to false negatives and would rather block real mail than have to wade through a mailbox full of spam. Others are more sensitive to false positives and would rather deal with unfiltered spam than risk losing mail.
At the ISPs, many of these decisions aren’t made by one person, but the decisions are driven by the business philosophy, requirements and technology. The different consumer ISPs have different philosophies and these show in their spamfiltering.
Gmail, for instance, has a lot of faith in their ability to sort, classify and rank text. This is, after all, what Google does. Therefore, they accept most of the email delivered to Gmail users and then sort after the fact. This fits their technology, their available resources and their business philosophy. They leave as much filtering at the enduser level as they can.
Yahoo, on the other hand, chooses to filter mail at the MTA. While their spamfoldering algorithms are good, they don’t want to waste CPU and filtering effort on mail that they think may be spam. So, they choose to block heavily at the edge, going so far as to rate limit senders that they don’t know about the mail. Endusers are protected from malicious mail and senders have the ability to retry mail until it is accepted.
The same types of entries could be written about Hotmail or AOL. They could even be written about the various spam filter vendors and blocklists. Every company has their own way of doing things and their way reflects their underlying business philosophy.

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