The volunteers are brought into a white tent. Inside sits a wise-looking, long-haired man in late middle age who calls himself Dave. He says he's a psychic.

You tell Dave your name. He hugs you and lays his hands on you. Then you and he sit down and he starts telling you things no stranger should know : your address, your romantic situation, your children's names, your medical history, how much you're selling your house for, your shopping habits, your bank balance.

You're amazed. You can't believe this guy knows so much about you. You can't understand how he does it.

Then Dave reveals his trick. A curtain comes down, and there's a room full of researchers on computers looking for your personal details online, feeding everything they find to Dave through a hidden earpiece.

As you sit there in shock, a TV screen displays the words: "Your entire life is online. And it might be used against you. Be vigilant."

This entire scenario actually took place recently in Brussels, Belgium, as part of "Safe Internet Banking," a campaign for online-safety awareness carried out by the trade association Febelfin (the Belgian Financial Sector Federation). The volunteers were passers-by, and Dave was an actor.

"Most people indeed spend a lot of time on the Internet and share a substantial amount of information about themselves through, for example, social networks," says the Febelfin website, somewhat hastily translated into English from Dutch. "You may not be aware of the fact that pretty much [all] of your private life may be disclosed online.

"This poses a problem, for Internet frauds also have access to this information and may use it for their criminal purposes. This will be all the more the case when you send an e-mail containing your bank card code number or log-in data."

Febelfin is right: Social media networks such as Facebook are treasure troves for identity thieves, who can easily discover the answers to such common password-reset questions as, "What was your mother's maiden name?"

The site's also got a lot of other useful information in Dutch, French and English, such as detailed tips for securing your Internet banking sessions, learning how to avoid malware and phishing scams, and keeping your computer fully patched.

Febelfin's also posted a series of informative instructional videos on YouTube. Unfortunately for most American readers, they're only in Dutch or French.