Privacy control. Personal-information protection. Identity control. All are great-sounding names for features you may have seen in your PC's security suite. But what do they actually do? (Compare Identity Management products)

To find out, I dug into the privacy features of the top suites from PC World's latest security roundup: Symantec Norton Internet Security 2008's Privacy Control (part of its free Norton Add-on Pack), Kaspersky Internet Security 7.0's Privacy Control, McAfee Internet Security Suite's Personal Information Protection, and BitDefender Internet Security Suite 2008's Identity Control.

With Symantec, McAfee, and BitDefender, you must define the information that you want to protect, such as Social Security and credit card numbers. Symantec and McAfee never prompt you to do so, but BitDefender alerts you until you either comply or tell it to stop. With Kaspersky, you don't give any instructions, since it automatically blocks malware that attempts to access your computer's Windows Protected Storage area, including sensitive Web-form information such as credit card numbers.

If the Symantec, McAfee, or BitDefender suite notices that your PC is about to send the information you registered over the Internet, the program blocks the transmission or prompts you to allow or disallow it. Symantec checks Web, e-mail, and IM connections, BitDefender scans Web and e-mail traffic, and McAfee handles just Web data. All three are limited to scanning nonencrypted connections, so they won't see anything you send to secure sites, but such https:// sites are mostly already protected. And since many Internet service providers accept e-mail only via an encrypted connection, the privacy apps can't scan those messages either. Generally, though, they can scan Web-based e-mail such as Google's Gmail, because most providers require you to use a secure connection to log in but switch to a nonsecure connection once you are in.

Symantec and McAfee prompt you to allow sending personal data, and substitute asterisks for the data when you choose to block sending it. BitDefender blocks outright any e-mail or Web pages in which you've entered personal data without giving you any option to make it do otherwise, which can be annoying.

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