Why is each one of these like all of the others?

What is the common bond between all of these things? Follow some links to find hints and the answer.

- Depression
- Heavy metal
- Dumb people
- Equilibrium
- Software documentation
- Piety
- Analytic philosophy
- Terrorism
- Market irrationality
- The difference between gambling and investing
- Sound science
- Urban sprawl
- Figuring out how to win