Spam deluge leads to search for silver bullet

Battle promises to be tough

He and other spam experts are pinning their hopes on Bayesian filters, which scan the entire content of an e-mail, including header and font information, and classify whether a piece of mail is spam.

The goal is to make these filters so effective that the response rate on spam becomes abysmally low, and spamming becomes a financially prohibitive venture.

"Make no mistake about it -- spam is a business," research scientist William Yerazunis told attendees at the MIT conference.

Yerazunis, who works at the Mitsubishi Electric Research Laboratories in Cambridge , is hoping to bankrupt that business by proliferating a Bayesian filter based on a programming language he wrote called CRM114. He claims the filter he created using CRM114 can block 99.9 percent of spam with a similar rate for avoiding false positives.

False positives, or wanted e-mail incorrectly identified as spam, is the key metric when it comes to evaluating antispam tools because the personal cost of missing correspondence from friends, family or business associates is high.

And as spam conference speaker Jason Rennie pointed out, dealing with spam is not simple, in good part because the definition of spam is personal.

Rennie, an MIT graduate student in computer science working on spam filters, underscored the importance of being able to personalize spam filters to some degree, by allowing the end-user to dictate what they consider to be spam. A lot of filter makers, and ISPs that offer spam-fighting tools, are taking pains to ensure their clients have as much say as possible about what winds up in their inboxes.

Although stopping the onslaught of spam is crucial to ISPs' business, given the bandwidth costs of delivering all that unwanted mail over their networks, it is also essential to ISPs not to inadvertently block legitimate e-mail through over-aggressive filtering.

Jim Anderson, vice president of product development for EarthLink said that the spam problem is a major issue at his company.

According to Anderson , EarthLink blocked and deleted 250 million pieces of spam last November alone, and the company is still hearing from customers that they want more controls.

"But the public policy aspect of the spam challenge is that you don't have unintended consequences," he said.