When surfing the Internet you probably take your anonymity for granted, most of us do. Tapping phones, listening to confidential conversations, reading others' e-mail messages seems like something that only happens in spy movies to "other" people. However, you probably don't realize just how much information about yourself has the potential to get transmitted across the Internet every time you go online.

Every computer connected to the Internet has "ports" that allow it to connect. A "port" doesn't mean you have a physical hole or opening in your computer's case or hardware, but it does mean you have openings through which information passes back and forth between your computer and the Internet. Depending on the type of connection (dial up, LAN, cable, DSL), you may have several openings for potential mischief by hackers, malicious code or viruses. Computers with dedicated connections rate the most at risk.

If someone or something gets into one of these ports and into your computer, they can potentially watch everything you do and see all the data you enter, including social security numbers and credit card information. The easiest way to defeat this problem involves using a firewall. Firewalls, simple and inexpensive software available at virtually any office supply or computer store, block the most common ports hackers use to enter your computer. Firewalls also help you detect and block unauthorized transmission of information from your computer to the Internet.

This adds a significant measure of protection if you get infected with a Trojan horse virus that tries to "phone home" to the hacker with your sensitive information. If you'd like to test your connection for vulnerability to attack, log on to http://security1.norton.com and run the various diagnostics.

I would strongly advise anyone connected to the Internet through DSL or cable to get and use a firewall to protect against unauthorized access. Infected with "Spyware?" Previously we talked about unauthorized access to your computer. But a growing problem online with people watching you and your activities involves using programs you willingly place on your computer. Commonly called "Spyware," this refers to any program that transmits information about you to someone else without you knowing exactly what gets sent.

The main purpose of Spyware involves tracking your surfing habits so advertisers know which targeted ads to send you. Most Spyware basically comes onto your computer bundled with other software applications, as a standalone program, or as modification to the HTML on a web page.

Regardless of how you get it, you need to understand exactly what information gets transmitted about you so you can decide whether to keep or uninstall the software. Plain and simple, these Spyware programs can potentially reveal extremely sensitive information about you and your online habits.