Unwanted email continues to clog the Internet in high volumes – often depositing malicious programs if it can slip past the filters meant to catch it, according to Microsoft's latest report about online security.

It’s not exactly good news for Microsoft Chairman Bill Gates’ famous prediction, in 2004, that the problem of spam would be “solved” two years from that point.

However, the report does show that Internet users aren’t actually receiving most of those unwanted messages. Using Microsoft’s Forefront Online Security for Exchange as an example, the Internet security report says about 97.3 percent of total email volume was identifies as spam and filtered out in the second half of last year.

That was down from 98.4 percent in the first half of last year. The company attributed the decrease to the disconnection from the Internet of McColo, a hosting provider that alleged spammers were known to use.

“The vast majority of the e-mail messages sent over the Internet are unwanted,” Microsoft said in the report. “Not only does all this unwanted e-mail tax the recipients’ inboxes and the resources of e-mail providers, but also the influx of unwanted e-mail traffic creates an environment in which e-mailed malware attacks and phishing attempts can proliferate.”

Gates made his spam prediction at the World Economic Forum in January 2004.  One of the potential solutions he cited was “charging” e-mailers in the form of extra computer cycles -- requiring the production of a digital code or “stamp” to deliver a message.

The idea was to making massive bulk emailing too expensive without affecting ordinary volumes of email. Microsoft Research explored the concept in its Penny Black project – named after the 19th Century British Postal System’s similar effort to shift the cost of mail to the sender, using stamps.

The Penny Black project at the company is no longer active, but Microsoft is still involved in a wide-range of spam-related research and prevention. In an email, a company representative pointed out that a lot has changed in the past five years:

"We’re continually evolving our spam-fighting technology to make it more robust and applicable to the current time. Technology from five years ago, like computational charging, is no longer effective today. With our technology advances, we’ve been able to reduce spam that enters customers’ inbox by 80% since 2006. ...

"We have succeeded in blocking nearly all of the techniques spammers were using in 2004. What we’re fighting today is the next generation of service abuse that’s significantly evolved in the last five years. We use an assortment of technologies to fight spam, which we don’t share publicly to prevent giving spammers insight into breaking the system. For information about what spam technologies we do publicly share, visit mail.live.com/mail/spamfighting.aspx."

Of course, some things never change: According to the report, about half of unwanted email messages tracked by Microsoft in the last six weeks of last year were for pharmaceutical products.