LONDON — Dinosaurs, so we are told, died out because they were too big. Or some say they were wiped out by an asteroid. No matter — all agree that their basic problem was size. They were just too large, their brains were too remote from their bodies, and their control systems could not cope.

Could the same fate now be overtaking the giant databases and centralized systems so beloved of modern governments?

In theory such centralization of data in society ought to make for more efficiency. Having every citizen's details and links with the state all gathered in one place is a bureaucrat's dream and sounds consumer-friendly as well. One single reference point instead of all those different offices and different forms to fill in — what could be better?