Intelligence is the combination of knowing a lot about a little while you also know a little about a lot.

Deep domain understanding helps you create analyses. Your ability to understand how a particular system (no matter how small) works allows you apply a confident analysis to new systems you encounter. Once you know everything there is to know about nuclear physics, soccer or the praying mantis, it makes it easier to understand new systems.

At the same time, it's impossible to be smart without also being aware of the wider world. That's because it's the random interactions and the surprising coincidences that help us navigate our daily lives.

The challenge of the net is that it made the large world a whole lot larger. There are the personal lives of your 1000 closest friends, on display, every day. Here is the news of the world, the whole world, not just what used to fit in the newspaper. And over there is every book ever published, every scientific discovery, every fringe political candidate.

Suddenly, it's a lot more difficult to know a little about a lot. It's tempting to spend ever more time pursuing that goal. That doesn't mean, I think, that you should give up knowing a lot about a little in order to devote ever more time to the noisy mosaic that's on your doorstep, nor does it mean you ought to give up and dive back into your hole. We've redefined worldly, but being an expert remains just as tough and important as it used to be.