“Privacy is no longer a social norm,” Facebook founder Mark Zuckerberg famously said.

He was 25 years old in 2010 when he made a speech saying: “People have really gotten comfortable not only sharing more information and different kinds, but more openly and with more people. That social norm is just something that has evolved over time.”

Of course, he would say that, wouldn’t he? He has made his millions – billions, probably – by encouraging his generation to reveal all online. But now unforeseen consequences have begun to emerge.

For example, it seems that universities may be rejecting potential students purely because of material, often fairly innocuous stuff, that they had put on Facebook or other social media.

It is a surprise to me that universities would bother to trawl through a teen’s social media postings in order to make a judgement – and even more surprising that they would judge them on postings the potential student had perhaps made a few years earlier. The early teens are a time when young people notoriously lack judgement.

And this is the core of the problem. Teenagers often post crazy stuff online – look at all those self-harm tweets after Zayn Malik quit One Direction – because they have rampaging hormones but they can’t see far enough into the future to understand that those tweets or Facebook messages they made at 13 or 14 could come back to haunt them when they are applying for university or for a job.

Social media has given youngsters the false hope that they are actually connecting with Zayn or Harry or whoever because they can become their ‘friend’ at the click of a button. And at the same time Twitter and Facebook gives them unprecedented access to their idols’ thoughts – and let’s face it, many celebs can be a bit, well, strange, to put it mildly, with many quickly cottoning on to the fact that the crazier the posting, the more publicity it generates for them.

Teens are natural hero-worshippers, so they are at risk of becoming unduly influenced by the mutterings of their idols, prompting them to up the ante on their own postings.

And then just a couple of short years later, when previous generations were able to think back to their own outlandish proclamations of love for some peculiar-looking chart-topper and laugh, knowing only their best friend knew about it, today’s teens have given away their own feelings to the world. And there it stays, in the public domain, for all to see. Teenagers are too young and immature to understand that the adults who run social media are duping them into surrendering their powerful right to privacy. Even worse, they have created a medium that allows you to invade other people’s privacy while retaining your own anonymity and remaining unaccountable.

The prospect of a world without privacy, a strangely distorted Nineteen Eighty Four with the role of Big Brother played by Zuckerberg, fills me with horror. And the dreadful thing is that we are doing it ourselves, every time we fill in an online form or buy something online.

The law has not yet caught up with the rise of social media but it needs to happen quickly before we sleepwalk into Zuckerberg’s world.