VNUnet has an interview with Vint Cerf (now with Google):
We have gone from simple switching in the phone
system to tubes to transistors to integrated circuits and that has had a profound effect. It has produced powerful, small devices using very little power.
Some people think Moores Law has been outgrown, but we keep finding yet more ways to tweak CMOS chip technology to make it run faster with less power, and its potential is not exhausted yet. We will eventually run out of capacity for that technology, of course.
The other dramatic change is in widespread high-capacity networks.
Today, we have computers in our pockets, embedded in cars, in the house and so on. The internet has 400 million machines connected to it not including laptops, PDAs, and the 2.5 billion internet-enabled mobile phones.
So we have two billion devices on the internet, but only one billion users. If we extrapolate that, we will have billions of devices interacting with an unpredictable effect on the network.