• Pick strong passwords. Use a mix of letters, symbols and numbers, following the guidelines at www.microsoft.com/protect/yourself/password/create.mspx.
• Use different passwords for different Web services. And never use your Web passwords for PIN codes on credit, debit, or ATM cards.
• Don't reveal sensitive information—not even in "private" areas of services such as Facebook or Flickr (YHOO) that offer public access to most material.
• Don't share files on services that offer optional sharing, such as Google Docs, unless there is a real need.
• Keep data whose disclosure would create legal liability or embarrassment on your personal hard drives and storage devices.
• Avoid file-sharing services such as Lime Wire that distribute pirated files. Both the services and the downloads can open your computer to prying eyes.
• Apply the latest security updates to all your software, including operating systems, browsers, and antivirus programs.