Tuesday, October 30, 2007

Is Google winning the spam wars?

I've posted on Gmail and spam fairly often. A year ago things looked pretty bad, but then I realized that my email redirection was poisoning the domain reputation algorithms Gmail used back then.

From Sept 1996 through July 2007 Gmail's spam filtering was doing pretty well, but in July they had a serious screwup. Mercifully by August it was under control and the results have been great for three months.

It seems Google's Gmail team has also noticed things are going well, today they declared light at the end of the tunnel. Google OS followed up with a bit more detail:
... Many Google teams provide pieces of the spam-protection puzzle, from distributed computing to language detection. For example, we use optical character recognition (OCR) developed by the Google Book Search team to protect Gmail users from image spam. And machine-learning algorithms developed to merge and rank large sets of Google search results allow us to combine hundreds of factors to classify spam," explains Google. "Gmail supports multiple authentication systems, including SPF (Sender Policy Framework), DomainKeys, and DKIM (DomainKeys Identified Mail), so we can be more certain that your mail is from who it says it's from. Also, unlike many other providers that automatically let through all mail from certain senders, making it possible for their messages to bypass spam filters, Gmail puts all senders through the same rigorous checks...
For years I've written that the way to defeat spam was through differential filtering based on the managed reputation of the authenticated sending service. This little blurb is consistent with Google implementing that approach.

Today about 70% of Google's incoming mail is spam -- but that's an improvement! It used to be closer to 80%. Excluding a weird 2004 bump this is the most prolonged drop in three years.

My inbox is looking pretty good, and I hardly ever find anything in the spambox now (though I only scan about 20% of what I delete, I get a huge amount of spam).

Gee. I have something nice to say about Google!

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