Mac OS X Snow Leopard and malware detection

"Malware" is an abbreviated term for malicious software. Malware includes viruses, worms, trojan horses, and other types of software that can damage the software on your system or violate your privacy. Malware can be installed on your computer when you download content or applications from the Internet, via email, text messaging, or websites. Mac OS X v10.6 Snow Leopard checks for known malware and alerts you so that you do not accidentally install it on your system.