The Fastest Global Diffusion of Technology in History

According to an excellent article Our Cells, Ourselves, written by Joel Garreau and published in Sunday's Washington Post, the number of cell phones in service, 3.3 billion, is roughly half the world's population. It took just 26 years to get to this point:

The human race is crossing a line. There is now one cellphone for every two humans on Earth.

From essentially zero, we've passed a watershed of more than 3.3 billion active cellphones on a planet of some 6.6 billion humans in about 26 years. This is the fastest global diffusion of any technology in human history -- faster even than the polio vaccine.

"We knew this was going to happen a few years ago. And we know how it will end," says Eric Schmidt, chairman of the board and chief executive officer of Google. "It will end with 5 billion out of the 6" with cellphones. "A reasonable prediction is 4 billion in the next few years -- the current proposal is 4 billion by 2010. And then the final billion or so within a few years thereafter.

I recommend the article - and also take a look at an article Calling From Where? from 26 years ago describing the first cell service in Washington. One optimistic pioneer predicted that "We're talking about 50 to 60 million over the next 20 to 30 years." Wrong!