Do Not Install Mac Defender

Cyber criminals have been working on socially engineering Mac users into willfully installing "Mac Defender" (a.k.a. "Apple Security"). The fake anti-virus app tricks people into thinking their computer is infected with a virus by popping up pr0n sites, and then offering to "fix" the "problem" in return for credit card information. It's difficult to protect unsuspecting users from themselves, but installing the free Sophos Anti-Virus for Mac Home Edition is a good start.