The question crops up every so often on Linux forums by those beginning with open source: where does one acquire anti-spyware software for Linux distros?
It's not necessary.
For many users, especially those converting from virus-laced PCs and, yes, even Macs, this may seem downright unbelievable. Protecting the computer from harmful programs comes as second nature to most computer users, often involving buying expensive anti-virus software just to keep the files safe from deletion or corruption on a daily basis. But it's true. On Linux systems, you really don't need to worry that much about spyware, hacking, and most other security issues.
The beauty behind the open source philosophy of Linux is that no piece of code, for instance malicious ones like viruses or spyware, can really hide. All is made completely transparent. While Windows and other operating systems trust virtually all incoming commands, Linux is based around an environment of untrusted users and networks, making it a much more difficult structure to crack.
Furthermore, the open nature of the code of the OS itself means that any potential security issues are quickly discovered, discussed, solved, and the fixes distributed through regular updates.
There is a less than perhaps ideal reason why spyware is less than prevalent as well. The relative scarcity of Linux users means that there's simply less of a market for the companies that profit from spyware and viruses to exploit.
All of these account for the distinctly pleasant lack of spyware that Linux users enjoy!