Both environments are dense, liquid networks

A metropolis shares one key characteristic with the Web: both environments are dense, liquid networks where information easily flows along multiple unpredictable paths. Those interconnections nurture great ideas, because most great ideas come into the world half-baked, more hunch than revelation. Genuine insights are hard to come by; it’s challenging to imagine a terrorist plot to fly passenger planes into buildings, or to invent a programmable computer. And so, most great ideas first take shape in a partial, incomplete form. They have the seeds of something profound, but they lack a key element that can turn the hunch into something truly powerful. And more often than not, that missing element is somewhere else, living as another hunch in another person’s head. Liquid networks create an environment where those partial ideas can connect; they provide a kind of dating service for promising hunches. They make it easier to disseminate good ideas, of course, but they also do something more sublime: they help complete ideas. 

From “Where Good Ideas Come From: The Natural History of Innovation” by Steven Johnson