Nicknames and Profiles
Never use personally identifying information when choosing an e-mail address or profile name: your name, sex, age or birth year, or your location. Instead, choose a "profile name" based on a hobby or other non-identifiable characteristic.

Smart Passwords
Change your password frequently. Create passwords as combination of special characters, numerals and letters. Do not use words in dictionary or personal details as part of your password since these are easier to crack.

Always Log Out
If you are using a public computer and a web-based mail, always be sure to log out of your account. Just directing the browser to a new page doesn't log you out, and leaves your account accessible to anyone else who sits down at that computer.

Read the Fine Print
Always read the privacy policy of a website before you type information into a form or share it with the company. If they don't have a privacy policy listed, don't share your information!

Treat E-mail Like Postcards
Never email personal or financial information, assume that it can be read by third parties.

Free isn't always Free
Be very cautious when downloading "free" programs online. These programs can include spyware, malware or viruses that jeopardize your personal information.

Check for the Lock
When submitting personal information online, always check the URL for https and a lock icon in the bottom right corner of your browser.

Know Who You Are Dealing With
Only do business with creditable companies.

Keep Up-to-date
Be sure that your anti-virus program is always up-to-date. Download and install patches (updates) for your operating system, firewall, browser, e-mail client etc.

Additional Resources

CERT: Safeguarding Your Data

CERT: Protecting Your Privacy

CERT: Choosing and Protecting Passwords

MS-ISAC: Unintended Information Disclosure

MS-ISAC: Safeguarding Your Data

MS-ISAC: How Anonymous Are You?

CERT: Supplementing Passwords