Media Perspective: The web's fusion of public and private media confuses us

Clay Shirky is, for my money, the best and most helpful writer about the internet and society there is. His last book - Here Comes Everybody - helped me understand a ton of what was going on online, distilling vague thoughts into coherent principles.

So when his new one - Cognitive Surplus: Creativity And Generosity In A Connected Age - slid through the letterbox last week, I pounced on it with great delight. It doesn't disappoint. There are revealing thoughts in every chapter and they're particularly important for people trying to do business on the internet, because they shed light on some fundamental motivations and forces that we often miss or misconstrue.

The best place to start is with his definition of media: "the connective tissue of society". It's "how you know when and where your friend's birthday party is ... how you know what's happening in Tehran ... how you know what your colleague named her baby ... how you know why Kierkegaard disagreed with Hegel ... how you know about anything more than ten yards away." He goes on: "All these things used to be separated into public media (such as visual or print communications made by a small group of professionals) and personal media (such as letters and phone calls made by ordinary citizens). Now those two modes have fused."

That explains a lot to me. It's obvious when you read it but failing to grasp the fused state of public/personal media is responsible for a lot of the things we get wrong online. We often take it to be a commercial, public media space (and we always seem to be looking for another small group of professionals out there to deal with) - but it's not just that. Things that are perfectly appropriate in public media just don't work in personal media. You wouldn't steam open people's letters and insert magazines ads, but that's sometimes how we seem to behave.

Mr Shirky also explains why the internet seems so full of low-quality content and yet everyone likes it so much. It's that the satisfaction of creating and sharing is so powerful that if you give the people the opportunity, they'll do it - even if the results won't challenge the professionals.

That's the beauty of internet memes such as LolCats. They're funny, but they don't just signal I'm Funny, Consume Me, they signal You Can Play This Game Too.

As Mr Shirky says, talking about all those online communities that make art directors blanch: "People don't actively want bad design - it's just that most people aren't good designers, but that's not going to stop them creating things on their own. Creating something personal, even of moderate quality, has a different kind of appeal than consuming something made by others, even something of high quality."

It's a great book. Get a copy. It'd be a good use of your Cognitive Surplus.