Today, tracking consumers is far more intrusive than the public realizes. For example, the top 50 websites in the US on average installed 64 pieces of tracking technology onto the computers of visitors, usually with no warning.
The "cookie"- a tiny text file put on your PC by websites or marketing firms which might be used to remember your preferences for one site,or to track you across many sites-is already old news. There are new and more complex tools such as "beacons" which scan in real time what people are doing on a webpage. These beacons instantly assess the Internet user's location, income, shopping interests and even medical conditions.
Tracking files get onto websites and are downloaded to a computer, in several ways. Often, companies simply pay sites to distribute their tracking files. But tracking companies sometimes hide their files within free software offered to websites, or hide them within other tracking files or ads. When this happens, websites aren't always aware that they're installing the files on visitors' computers.
Tracking companies are often staffed by math gurus with expertise in quantitative analysis. Some use probability algorithms to try to pair what they know about a person's online behavior with data from offline sources about household income, geography and education, among other things.
Personal data gathered from such tracking is now bought and sold on stock market-like exchanges.
The new technology is now exerting a profound impact on the Internet industry, especially on how retailers locate and sell to their customers. Millions of Internet users around the world also face unprecedented threats. Private, sensitive, personal and business information is being gathered and sold without their knowledge.
Companies insist the information they gather is anonymous and the data is used harmlessly. But the technology has grown so powerful and evasive that even some of the biggest websites in the US don't know that they were installing intrusive files on visitors' computers. These include MSN.com and Yahoo.com.
Next time you visit a webpage and find an ad banner advertising something you've been planning to buy, don't be amazed that your computer can read your mind.