I fall victim to Tickle Master Vince while at work.
Also, if you're just casually chatting with someone, and answer that a/s/l question (age, sex, location for those of you who are chatting newbies) the only other question you'd have to answer is "What's your last name?" for someone to start searching the Internet for you. And the likelihood is, they'd find you.
There are plenty of search sites to locate people out there. In fact, several directories now have reverse look-ups, meaning I can type in your email address, or your phone number, or your address, and find your name. In some states, I can pull up your driver's license onscreen. Scary? It's not that hard. You don't have to be some computer whiz kid or private eye to do it, either.
It can be as simple as going to Google and typing your name in quotation marks. Think I'm kidding? Try it. Go type your name into a search engine: "John Doe" and see what comes up. Did you find yourself? If you didn't, try adding your location afterward: "John Doe" Idaho, and see what comes up. What you find might be eye-opening, and even scary. All someone needs to know is your last name and location, and there's all sorts of things they can find out about you.
Remember: if you can find you, so can they!
Another issue develops when you have a personal web site or blog. Many people are very open, sharing information about friends and family, but this can backfire if you get into a cyber-stalking situation. It's safest just not to do it from the start. It's obvious to say don't post your personal information: full name, address, phone number. Duh! Right?
But I would go further. Don't use your real name and don't use your children's real names. There are lots of family blogs out there that have gone to using pet names or nicknames or initials when talking about family members ("Baby Boo" or BB) instead of using real names. This is preferable. And if you post pictures on your blog or website, be careful to exclude any with identifiable location features-sweatshirts with school names, recognizable landmarks, etc.
The other thing about websites to be aware of is the WHOIS lookup. Did you know that anyone can look up who a web site is registered to? And what comes up will include all of your personal information: name, address and phone number. Make sure, if you have a web site, you go through a company that will allow your WHOIS information to be anonymous!
Your email address is also an issue, especially if you have a local Internet Service Provider (ISP). The safest thing to do is use a website-based email service for anything you do online. Hotmail, Yahoo, Google-they all have email services that are free and allow you to send and receive email without revealing any personal information. (Just be careful not to fill out too much in your profile!) If you use the email that your local Internet Service Provider gives you, your email headers will reveal way too much information you didn't realize you were sharing, including your location, your ISP, and sometimes even your real name! If you want, you can even sign up for a free, anonymous email service (gmail offers it) that will provide forwarding of email messages to your ISP email address.
Be careful if you or your family are using an Instant Messenger service.