None of my business

Privacy is a mutable concept. Most of the time most of us never think about it. Roger Clarke, who's Chair of the Privacy Foundation and was on Friday's talkback, puts it very succintly: "It doesn't matter until it does." This is a pithy, IT-expert's way of saying that none of us care about privacy until we feel ours has been invaded.

I think that's right but also not the full story. It's likely I would feel my privacy is being invaded at a different point to when you would. Certainly, there's a difference between generations. Older Australians have a more attenuated sense of privacy, younger ones much less so. So a person in her 70s, is less likely to tell you how she votes or what her house cost, than one in her 40s.

Young people, for whom social networking sites like MySpace, Facebook and Bebo are de riguer, are extremely relaxed about privacy. Or at least, that's how it looks. I use Youtube to find old music clips when I'm supposed to be working but there's plenty of other, more embarrassing, footage out there. And spend five minutes flipping through bebo.com or myspace and you can see images of worse-for-wear party-goers that would not have been in the public domain a decade ago.

A couple of things are going on here. Firstly, these images are not being posted so the likes of me can pontificate about 'young people today'. They're not aimed at me at all, they're for their friends and acquaintances. Interestingly, Jonathan Nicholas - Director of Inspire Interactive, says the fact that anyone can see these pictures doesn't really occur to many people who post them(!)

But it's not just naïveté. This is the Big Brother generation (in the Endemollian sense rather than the Orwellian). It's used to the idea of a life lived in public - that's what the nobodies selected for the tv show do and it's what the high status celebs do too. Using myspace enables you to control your image as professionally as the craftiest PR firm, so why would you want to hide your light under a bushel?

However, you can't do this if you have a privacy threshold set at the same level as say, a 75-year-old's. Naturally there are 75-year-old exceptions to that rule - Joan Collins springs (unbidden) to mind, and I don't think any of us are looking forward to this guy getting older in his usual understated, discreet manner.