Mark Zuckerberg on Thursday gave a passionate defense of how Facebook Inc and the rest of the Internet are essential tools for the free expression that is essential in a healthy democracy. I agree with this in principle, as I imagine most Americans would.

The dark side of Facebook and the mass-market Internet is not necessarily the ideas behind them. It is how those principles can wittingly or unwittingly be subverted when principle meets reality. The question is whether the good that comes from anything – Facebook, the automobile, electricity – outweighs the inevitable negative effects and whether it’s possible to mitigate the latter while accentuating the former.