TV, radio, outdoor and press have all been revolutionised by technology, choice, diversity and fragmentation. Cinema is the only medium I can think of which has stayed fundamentally the same in the last 20 years.
Okay, you don't get chandeliers at modern cinemas, or balconies, they now smell of popcorn rather than cigarettes and they have got rid of the still-shot ads of the Taj Mahal Indian Restaurant, but the basic offering is the same and long may it continue.
But if you're examining change, it is online which provides the most fascinating study. I recently attended a workshop about the internet and how consumers were using it to change their lives. I left there feeling a bit frightened and a bit exhilarated at how the world, never mind media consumption, might change in the next few years.
Take the internet's affect on business. It is now the norm for people to organise a holiday without consulting a travel agent.
People are more self sufficient and less dependent on business via information sharing.
Everyone loves eBay. I'm sure someone, somewhere, has calculated the millions of pounds lost to traditional shops and businesses because of the frenzy of trading on eBay.
In many ways, the net could return us to anarchaic system; the exchange of goods, rather than buying and selling, will provide subsistence. I have a chicken, you've got some oranges: bargain.
There will always be someone in the world who desperately wants what you are selling. I've just been looking at my local free ads paper. Here's a sample: Petrol can, £1; Candarel tablets (500), brand new, will take £3.50; about seven old blowlamps, as found, £7; E45 cream, pump action tub, £3 each or £5 for both.
I love these. How can you have "about seven" of anything? And the E45 one – imagine this person wracking their brains to think of anything descriptive to say about the product and then pulling "pump-action tub" out of nowhere, like it was some sort of desirable accessory. But the best bit: £5 for both. They've only actually got two to sell! I almost cried when I read that.
The point is, these items may struggle to sell in my local area, but someone in the world will pay for these things, even the petrol can. Rip off Britain? We now have the wherewithal to rip each other off instead. And that's much more fun – eBay is just the start. Finally I can see how the internet will revolutionise the planet.
Adrian English is associate media director at Carat.