"Once you had data, you could build theories. Once you had theories, you have predictive power, you could test that and then the whole thing fitted itself. It suddenly very actively emerged as a field that we now call network science. Going beyond networks, going beyond connectedness, we realized we started to know not only whom you connect to and whom you see and where are your links (the economical, personal, social or whatever they are) but we started to see also the timing of your activities. What do you do with those links? When do you interact?
That was the second way; we called it 'human dynamics.' It describes what do we do in real time, because if you think about it, social sciences have been trying for a very, very long time to try to describe human behavior. They did a really good job delivering a set of tools for how you measure a person's activity, but much of that was really based on observation, based on small samples and based on interviews and questionnaires. What has happened in the last decade or so is that thanks to the many activities we have, and thanks to the many digital devices that we carry around, much of our activity became completely recorded. We got to the point that there's so much data recording happening around us, that pretty much somebody who lives in a big city in Western Europe or in the United States, much of their life, almost in minute resolution, can be reconstructed from the many data streams that we leave around us.