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December 1, 2005

Blacklist stats suggest anti-spam progress

Have we turned the tide in the battle against spam? Experts fling around a lot of contradictory statistics about overall spam volumes. But here's one figure that might give cause for cautious optimism.

For four of the past five months, the number of addresses on the SPEWS anti-spam blacklist has declined. According to figures compiled by David Bolt, there are currently 27,082,798 Internet protocol (IP) addresses on the controversial list of spam sources.

That's down nearly 350,000 IPs since the start of November 2005. The SPEWS list also shed nearly 120,000 addresses in October.

There was a slight uptick in September 2005, following huge drops in August 2005 (-540,000) and July 2005 (-1,082,000).

Now, here's the bad news. In December 2003, when Bolt first began publishing his analysis, the SPEWS list contained a total of just 12,635,013 IP addresses. In other words, since CAN-SPAM went into effect, the SPEWS list has more than doubled in size.

Meanwhile, the percentage of the total Internet space being blacklisted by SPEWS has more than doubled as well. In December 2003, SPEWS blocked 0.294 percent of total IP space. Currently, around 0.631 percent of overall IP space is being blocked.

What's more, the recent gains could be easily wiped out if SPEWS decided to make another one of its radical statements about rogue ISPs.

Clearly, it's too soon to declare that spammers are being driven off the Internet. Still, stats from the last few months suggest a trend in that direction. And compared to this time last year, when there there were 27,907,148 IP addresses on the list, the size of the blacklist has shrunk three percent. Woot.

(For those who want to crunch the SPEWS numbers themselves, Bolt provides software.)

Posted by brian at December 1, 2005 10:42 AM