Reading about the latest phone- hacking scandal involving the News of the World, it's easy to think the biggest threat to our privacy today is not from nosy governments, but from tabloid newspapers and other businesses who like to pry.

But rewind a few weeks and recall the story about the spy chief's wife putting her family's personal details on Facebook, thus exposing him to security risks.

The biggest threat to our privacy is our own ignorance.

It's the way we think that texting a message or posting something online is as secure as a private chat between two people face-to-face.

It's not, and this sort of stuff never has been. Back in the dinosaur age, when you made a phone call, a woman at the GPO used to plug the line in and maybe have a little listen.

Many of you might remember when those lines were scarce, or expensive, and you shared one with the folks next door – the notorious party line, which was prone to crossing and eavesdropping.

When did we get so stupid as to blur the boundaries between our private and public thoughts, and to imagine that our digital communications had the sanctity of the confession box?