One of the things about the Estonian model is that it emerged after the Soviets left Estonia. They really had very few services, very few business processes in place, almost no infrastructure in place, and they really needed to build a state from scratch.
I think the Estonians were lucky in that they started to do this at the very same time the Web was emerging. Rather than trying to simply replicate the way state services had been built in other types of governments, they looked at how people were building software on the Web—distributed systems with canonical datasets—and so they started to simply say, we're going to do something really different. They were actually forced by the fact that they had very little money, so they said, we can't afford to replicate all of these systems in every single ministry.
You had a very specific point in time with a very specific history, with a relatively young leader who was willing to give political cover to people who were trying something very different. Those are the historical roots of how Estonians ended up doing what they did. One of the reasons why I think they're a wonderful model to look at—but probably not a wonderful model to try to emulate—is that their situation was so unique.