For example, this graph shows the adoption rate of iPods, iPhones and iPads in the months after they were first launched. The iPad is the fastest growing device ever. Way faster than iPhone and you can barely see iPod early adoption (the green sliver at the bottom). And that was a product that many people (including me) thought "why would I want an overgrown iPhone that doesn't even make calls". Now I find I use it more and more and I really only use my MacBook for input heavy stuff like writing and putting business spreadsheets together. In fact almost a third of US adults already have a tablet or eReader. So all you companies giving away iPads at DAC: nice, but we've got one already.
Android adoption is perhaps even more amazing. Of course this is aggregating many suppliers, and nobody is getting rich on Android adoption (even Google makes more money on search on iPhone than it does on Android). But it is already over half the market for smartphones.
Mobile is huge, already over a trillion dollar industry. But more importantly is that it is increasingly the way people access the internet, now up to 10% of all traffic. Facebook's big weakness is it doesn't have a way to monetize people on mobile. People won't tolerate lots of ads on the small screen, the display real-estate is too limited. Latest rumors are Facebook is going to build their own phone. Like it's going to be so good that people would rather access Facebook on it than using an app on their iPhone. I don't see how that is likely to be successful?
One more factoid. Print takes 7% of the time we use media but still has 25% of the advertising dollars, although falling fast (the New York Times revenue is falling off a cliff, for example). Radio, TV and Internet are fairly balanced. But mobile consumes 10% of our time but only 1% of advertising dollars. I hope this doesn't change too much in a dumb way, since as I said above the screen is so small that ads are really intrusive on a phone. But the numbers show the size of the opportunity. And it will only grow (fast).
And don't forget to amaze your grand-kids one day with how we used to build little houses for telephones, so small you couldn't even sit down. They won't believe you...
You can see the whole presentation here.