I'm coming up now for my one year iPhone anniversary and I note that even primary school kids seem to have iPhones these days.
The difference between the ad agency guy and me is that he's one of the early adopters in this market and I'm one of the early majority. Doesn't sound like a huge difference, but it is. We tend to think of the adoption curve for new products as continuous, but it's not, always. If you're not familiar with it already, I recommend a look at a book from 1991, Crossing the Chasm by Geoffrey Moore. And in this book, you'll see that, for discontinuous innovations - those requiring a behavioural change, there is a huge difference between those two "early" groups. A chasm, in fact. The guy from the agency is a visionary. I'm a pragmatic conservative.
Crossing the chasm between these two psychologically vastly different groups is even more relevant these days. With the fast churn of technology, there are simply more discontinuous innovations around. This may explain the huge interest in behavioural economics amongst the marketing community. And, it's also vital to hang onto your visionaries aka early adopters for long enough to let you cross the chasm, before they flit off to this month's (week's?) thing.
The book was originally written with hi-tech markets and products in mind. But the theory may also be applicable in areas where a behavioural change is required - like moving to a carbon-neutral lifestyle, for example.
And that may be a chasm we're all going to have to cross one day.