Check the retailer's privacy policy, too. It should specify what they will and won't do with your information. (Note that those policies change, especially when a company changes hands). You'd be surprised how many sell online merchants sell your e-mail and address to third parties. Search the privacy policy for terms like third-party, e-mail address, or personally identifiable information; that should help you find out what a retailer plans to do with your information.

Assuming you are working with a reputable merchant, be sure you are actually on the correct site. A phishing attack or network redirection attack can direct you from e-mail or another Web address to a fake site (which may look exactly like the real thing). One Firefox plug-in, can help: It makes clear what Website you are using.

Also, many attackers go to great lengths to make their domains look like something that plausible-- http://amazon.com.itakeyourmoney.ru, for example, might look like the real Amazon at first glance, if you don't check the end of that URL. And they're never that obvious.

Regardless of your best efforts, your information may still be compromised. That's why it's also important to monitor your identity through services such as , , and ). They will alert you when any new credit requests appear in your file. Get into the habit of checking your credit card and banking accounts frequently to make sure there are no unauthorized charges.