READ THIS: A type of CAPTCHA, or image-degradation model, known as EZ-Gimpy tries to outwit computer bots with distorted letters and busy backgrounds. A human user easily recognizes the word and types it in the blank, allowing entry to a Web area. Image: CARNEGIE MELLON UNIVERSITY
Three years ago rogue computer software programs called bots posed as teenagers in Yahoo's chat rooms on the Web. There they created mischief by collecting personal information about the teens who visited or by pointing chat participants to advertisements. The bots operated by waiting until a visitor typed a question mark. They would then automatically create a response about where a person could find an answer and provide a URL that would deliver the visitor to an advertising site.
Bots are well known for helping to generate millions of spam messages advertising printer cartridges, septic systems, Viagra and Nigerian money scams. They disseminate junk information by opening up new e-mail accounts and then automatically delivering a flood of messages. During 2001 estimates of the volume of spam reached more than six times that of a year earlier. And last year the volume was 21 times greater than in 2000, according to the Coalition against Unsolicited Bulk Email, an Australia-based organization.
This article was originally published with the title Baffling the Bots.