Inside Snow Leopard’s hidden malware protection (Macworld.com)

Macworld.com – While malicious software has long been a near-daily annoyance for Windows PCs, Mac users have become accustomed to not worrying about malware. Threats arise from time to time—in January of this year, for example, a Trojan horse made the rounds in pirated copies of Apple’s iWork software—but most Mac users these days are probably running computers without antivirus software.