Bugs can, however, be written to reach across the Internet into unprotected computers and steal files. For that, he can turn to a growing array of privacy-enhancing products designed to make Web surfing anonymous. By masking the numerical Internet address that identifies a user's computer, Web sites are prevented from tracking the user, who effectively surfs under an alias. Dozens of other privacy protection products exist, including Privada, Anonymizer, IDzap and Somebody. Typically, they offer anonymous surfing and multiple aliases as well as management of the so-called cookies.
Some cookies are desirable, like the one from a bank or online broker that remembers a password.
Web bugs can be fairly innocuous, providing advertisers with data on who is visiting a Web site. Or they can be intrusive, passing information that surfers enter into online registration forms to advertisers or marketers, Smith said. So it's sort of putting social pressure on Web sites. But privacy-enhancing software has its drawbacks. First, it can hamper performance because some services route through private servers that can make surfing slower.