With Vista, Microsoft introduced a new security concept to help protect your computer. Rather than relying on discretionary controls, like NTFS file and folder permissions which users can assign and change, Vista also has new mandatory controls. WIC, or Windows Integrity Control (also referred to as MIC, or Mandatory Integrity Control in some circles), assigns an integrity, or trustworthiness, level to each object and uses the integrity levels to control interactions between the objects. The integrity levels are assigned by the operating system and supercede, or override, the dicretionary permissions to protect the computer system. WIC is used throughout the system, but is arguably most noticeable in the Internet Explorer Protected Mode which protects the Vista operating system from malicious web content in Internet Explorer. For more details about WIC, check out this article I submitted to SecurityFocus: Introduction to Windows Integrity Control.