Katy Guest: No cyber-secret is ever safe

It's now easier to be duplicitous - and easier to be found out

It was H L Mencken who wrote that nobody ever went broke underestimating the public's intelligence. But the great journalist and professional cynic clearly didn't anticipate the 21st century, in which a major company slipped up by doing the opposite – though in this instance it was more a case of overestimating the public's sense of morality.

The mighty Google thought it would be a great idea to create a social networking site by plundering Gmail-users' email contacts books and kindly making users' contacts into Facebook-style "friends" for them. It hadn't occurred to them that some people might not want all their contacts to know who else they have been contacting. Some things, thank you Google, really ought to remain our little secret. Sorry if you're very disappointed by our murky G-subterfuge.

A similar cold hand of panic grips Facebook-users when a spam message arrives promoting an application that can tell you who has been looking at your profile page. It would be fascinating to know which pathetic little weirdos have been tragically stalking one under cover of e-darkness, of course. But nobody wants that enough to allow anyone else to know when we have been looking at their profiles.

It is nothing more sinister than entirely natural human curiosity that makes a person want to find out how their ex is looking these days (gratifyingly rough, as it happens). But some sad people might take that healthy curiosity out of context – in particular, gratifyingly rough-looking exes, the arrogant little morons. So it's a good job that the mythical snoop application remains nothing but a salutary fiction, for now at least. Facebook, thank goodness, understands that some of its users have secrets.

The problem with modern technology is that, while it makes it exponentially easier to be duplicitous and underhand, it also makes it so much easier to be found out. Just ask Vernon Kay how temptingly simple it seemed to send saucy phone messages to raunchy textophiles none of whom was his wife.

The "sex text" appeals, it turns out, to the desperate, the exhibitionist, the very stupid and the alarmingly ambidextrous, which must be why footballers are so keen on the format. David Beckham allegedly had an epistolary extra-marital friendship a few years ago which was said to have involved the Napoleonic line: "I really wish we was in your bed now." A line that was preserved in perpetuity the minute his errant thumb pressed the send button – the silly boy.

It would be sad to believe that social networking is mostly made up of antisocial behaviour: cheating on partners; checking up on exes; meddling maliciously in other people's affairs. But it is always worth bearing in mind how one's innocent written comments might look to others.

Mencken was ahead of his time when he wrote that "conscience [is] the inner voice which warns us that someone may be looking". If they're not looking now, they probably will be very soon. Cheaters beware: there is no such thing as a secret in cyberspace.