Amazon suggests.....
Cyberspace knows you. It follows you, tracking your every move. It stalks you. Online merchants are ready to move in for the kill.
Many retailers, such as Amazon.com, track your searches, the items you view, and your purchases. They use this information (so they say) to help provide you with products you may be interested in, as well as keep statistics for their own site improvement. This may seem fairly benign.
We can also be tracked in more malicious ways, however. Each time you access a site, your IP address is recorded, along with other vital information. It therefore becomes difficult to surf anonymously—websites can know all sorts of things about you. For example, this piece of code (danasoft.com) read my IP address, operating system, internet browser, and knew that I was using Brown's internet. 
Perhaps it won't work on everybody's computer, if they have appropriate firewalls or other security software installed, but it certainly knew my information.
The network can also infiltrate your computer in secrecy. Spyware or cookies can be downloaded onto a machine without the user knowing, and record site history and any passwords or identification numbers entered. A malicious thief can use this stolen information with devastating effect, such as in identity theft.
The Patriot Act now gives the government special privleges to access electronic information. Email, voicemail, or pretty much any data on a network server can be surveyed. Anything on the vast network becomes fair game.
Perhaps the public doesn't approach the networked world with as much caution as they should. Your identity is out there, naked, for all to see.