Microsoft on Friday provided an update on its ongoing war against spam, claiming that it has cut spam on the Hotmail web-based email services by some 90 percent and, in doing so, has also cut overall spam on the Internet by 15 percent. As important, it's cut so-called "outgoing spam"--i.e. that spam that is sent from Microsoft's Hotmail servers--by an impressive 75 percent as well.

"Spam is a huge problem that continues to plague the Internet," Microsoft's Dick Craddock wrote in a blog post on Inside Windows Live. "Historically, more than 90% of all email sent has been spam, and spam affects every email provider. Spammers do what they do because it’s profitable; they need only a few people to click on the spam messages in order to make money."

According to Craddock, since the height of Hotmail's spam problems back in 2006, the company has made huge strides. And since its last update on its progress against spam, Microsoft has worked to continue lowering the overall "Spam in the Inbox" (SITI) score on the service. If I'm reading the accompanying chart properly, it appears to be doing quite well, especially over the past 12 months.

siti_hotmail_2011_0

"We've reduced the level of spam in Hotmail by 90 percent since its peak in 2006," Craddock explains. "Since last year, we've reduced what was left by another 40 percent (from 5 percent true SITI to 3 percent true SITI)."

Interestingly, the peak of spam on the overall Internet occurred in 2008, according to Craddock, and that 15 percent figure dates back to that time period. (The 90 percent reduction figure dates back to Hotmail's peak time for spam in 2006.)

There's some good information in the post about the methods that Microsoft uses to combat spam, and it's not all technology related: The software giant also aggressively pursues spammers (and related Botnets) with legal tools and in conjunction with law enforcement agencies. (This is not something you see Google doing, at least not this prominently.)

Craddock promises a future, related post on phishing attacks as well. Interesting stuff.