So by now you will all have heard of Twitter, the micro-blogging site on which Stephen Fry and Lily Allen tell you what they had for breakfast in 140 characters or less.

It’s also the go-to site if you wish contravene a Premier League footballer’s super-injunction or start an uprising somewhere in the Middle East.

Like many people, I tried Twitter out a while back and found it slightly bemusing. I went online, I registered my user name and then told everyone what I had for breakfast, because I heard that this was what people did. Theoretically, my tweet could be read by any or all of the many millions of users on the site.

But I’m pretty sure no-one noticed it – it turns out that in cyberspace no-one can hear you tweet – unless that is you have lots of followers. But it’s Catch 22 – you don’t want to tweet if you have no followers and unless you do tweet no one will ever follow you.

So I did the sensible thing and went back to Facebook which I at least vaguely understood.

But slowly Twitter drew me back in, primarily as a spectator. It turns out there is plenty of interesting stuff out there if you know what to look for – a lot of news stories hit Twitter before they ever reach the TV bulletins. Plus, people say funny things (many of them un-breakfast-related) and there is intrigue, scandal, and feuds –all in 140 characters or less, of course.

You also quickly realise that Twitter has a very rigid hierarchy. I recently heard it described as the electronic version of the school playground. It’s a place where you can listen to all the cool people talk to each other. Just occasionally we ordinary, uncool people attempt to join the conversation and we are blanked, just like we were at morning play-time all those years ago.

Which brings me on to the case of Russell Crowe, who made what he thought was a very witty comment about circumcision to his Jewish friend, movie director Eli Roth. He tweeted: “I love my Jewish friends, I love the apples and the honey and the funny little hats but stop cutting your babies.”

However, Crowe, being (he supposed) one of the cool guys in the playground, forgot that he had a couple of hundred thousand followers hanging on his words of wisdom and many of them were offended by the comment – so much so that Crowe, no doubt with visions of his disgraced compatriot Mel Gibson at the back of his mind, very quickly and very profusely apologised for upsetting anyone – in 140 characters or less, obviously.

Roth defended Crowe. This, he said, was a private joke. Well if so, why broadcast it to millions of people? Maybe one of Crowe’s entourage should teach him how to send texts to his buddies instead.

I too have recently begun to tweet regularly, though in light of Crowe’s experience I do have some sensible ground rules which I always follow. These are: never tweet after you’ve had more than two drinks, particularly if you have been pondering the subject of circumcision. If you plan to insult the Syrian authorities through Twitter, ensure that a. you are not in Syria and b. your profile photo is of someone other than you.

Oh and don’t bother tweeting about what you had for breakfast… unless, that is, Ryan Giggs happened to be there at the time.