The ability to control what information one reveals about oneself over the Internet, and who can access that information, has become a growing concern. These concerns include whether email can be stored or read by third parties without consent, or whether third parties can track the web sites someone has visited. Another concern is whether web sites which are visited collect, store, and possibly share personally identifiable information about users.
The advent of various search engines and the use of data mining created a capability for data about individuals to be collected and combined from a wide variety of sources very easily.

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