Spam Filters Work: FTC

Amid a string of grossly self-serving reports from Internet security firms that the vast majority of e-mail traffic is spam comes a little-noticed report from the Federal Trade Commission claiming that ISPs’ spam filters are keeping most unsolicited e-mail from hitting people’s inboxes.

During an unspecified five-week period, one unnamed provider of free e-mail addresses prevented 93% of spam from hitting inboxes while another blocked 78%, according to the FTC.

In the study—published in an appendix of an FTC report outlining the findings of its recent anti-spam summit—the agency said it established 150 anonymous e-mail addresses, 50 each with two ISPs that use spam filters and 50 with one that uses no spam filters. The FTC said it then posted the addresses on Web sites, message boards, chat and social networking sites, and video posting sites.

After two weeks, the 50 unfiltered addresses received 718 spam e-mails, according to the FTC, while the 50 addresses at one of the filtered ISPs received 55 messages and the addresses at the other filtered ISP received 231.

After five weeks, the 50 unfiltered addresses received 3,045 spam e-mails while the 50 addresses at one of the filtered ISPs received 202 unsolicited commercial messages and the addresses at the other filtered ISP received 664, according to the FTC.

The agency said the study determined that addresses posted on Web sites were far more likely to be harvested than those posted on other Internet locations, such as message boards, chat rooms and blogs.

At the end of the first two weeks of the study, 86% of the spam hitting the FTC’s decoys was to addresses that had been posted on Web sites, while 14% was to addresses posted at other locations, the agency reported.

“The fact that the vast majority of spam sent to harvested addresses in this study was never delivered to consumers’ inboxes demonstrates the relative effectiveness of the two ISPs’ spam filters,” the report said.