Internet baby-sitting software is a con. It is no coincidence that the companies that sell it are usually the same ones that sell anti-virus software. Not because they are both security products (they aren't) or because they use similar technology (they don't) but because they both require marketing departments who know how to sell snake oil.

Consider; yesterday we were told that the company CyberSentinel (which produces the software CyberSentinel) had paid for a survey to find out what (and how much) filth teenagers look at on the internet. The "shocking" results looked pretty much like the program schedule of most of the Freeview TV channels: shopping, dieting, cosmetic surgery and chat. And the porn? 87 hours a year. A year! And they were including soft porn, which you can also easily see on TV (In fact, after 12pm, it's quite hard to avoid). 87 hours a year is less than a quarter of an hour a day. I grew up in the 1980s before the web was invented and I spent a lot more than 15 minutes a day involved in the pursuit, acquisition and consumption of porn.

Official marketing droid quote: "The alarming thing about this research is that it shows that teenagers are obviously exploring all sorts of topics as a result of modern-day pressures [and] they find it easier to go online to conduct their research than asking mum and dad for advice." Really? That's alarming?

So in other words, the problem they are attempting to solve doesn't really exist. But even if it did, automatic net monitoring software would not be the solution. The solution is to talk to your kids and keep an eye on what they are up to. Obviously leaving them on their own in their bedrooms with a laptop and a broadband connection for hours at a time is a bad idea. But leaving teenagers unsupervised doing anything is a bad idea. Didn't you get the memo? That's what teenagers are like.

If you rely on filtering software to keep your children safe online - or even if you just use it as an extra line of defence - then you are guilty of delinquency. The mere fact that it is installed on your PC will create a false sense of security. False because filtering software doesn't catch everything. False because your kids are easily capable of figuring out how to get around your trivial security measures. False because there are lots of other unsecured computers they can use.

You don't keep your children safe in the real world by putting an electronic tag on their ankle while you slope off to the pub every night. Strange then that this seems to be precisely the recommended strategy to keep them safe online.