For a month or so earlier this year, DoubleClick Inc., an Internet advertising firm based in New York, furtively put up three different editions of its home page. Most visitors saw one version, highlighting the firm's accomplishments. Employees of a rival firm could see only another version, with a special press release touting DoubleClick's capture of one of the rival's customers. Clients being wooed saw only a third version. It also offers a reminder that going online is hardly a private affair.
Most people think that browsing the Web is as anonymous as watching TV or reading a newspaper.
Even venture capitalists have to worry. New Internet firms have surreptitiously watched which investors visit their sites, and how often. This tracking tells them who is the most enthusiastic about their venture, and thus whom they should pursue for money. Companies also use this intelligence to size up potential suitors in acquisitions. They huff out of the room, saying they're done, and then the company sees lots of hits on their site from those same people.