Spyware refers to programs which gather information on the user of the computer they are is installed on, thenwhich is sent to the software's publisher so Internet users can be profiled.
Data gathered this way may be:
Spyware programs generally are installed along with other software (mostly freeware or shareware). This enables the creators of such software to make their programs profitable by selling the statistical data, allowing them to distribute their software for free. It is a business model in which the product is given out for free in exchange for data of a personal nature.
Spyware is not illegal, as the accompanying software's end user license agreement makes it clear that the third-party program will be installed! On the other hand, as users rarely read the long EULA in full, they very rarely know that the software is building a profile of them.
What's more, besides the damage done by divulging personal information, spyware may also cause various other nuisances:
Spyware is usually divided into two categories:
The main trouble with spyware is detecting them. The best way to protect yourself is to not install any software whose origins and trustworthiness you are not 100% sure of (in particular freeware, shareware, and more specifically peer-to-peer file exchange software). Here are a few examples of software known to come with one or more spyware programs (this list in non-exhaustive):
Babylon Translator, GetRight, Go!Zilla, Download Accelerator, Cute FTP, PKZip, KaZaA and iMesh.
What's more, uninstalling this kind of software only rarely removes the spyware that was installed with it. Worse, uninstalling it can cause other applications to malfunction!
In practice, it is nearly impossible to avoid installing any software. For this reason, the presence of suspicious background processes, strange files, or worrisome entries in the registry may sometimes indicate the presence of spyware on the computer.
If you don't go over the registry base with a fine-toothed comb every day, don't worry. There is anti-spyware software for detecting and deleting files, processes and registry entries created by spyware.
What's more, installing a personal firewall can both detect spyware and prevent them from accessing the Internet (and therefore from sending the data collected).
The best-known and most effective anti-spyware tools include: