Popular as Keynesian fiscal policy may be, many economists are skeptical that it works. They argue that fine-tuning the economy is a virtually impossible task, and that fiscal-stimulus programs are usually too small, and arrive too late, to make a difference.

The desire for reinvention seems to arise most often when companies hear the siren call of synergy and start to expand beyond their core businesses.

In order to work well, markets need a basic level of trust.

Unlike most government programs, Social Security and, in part, Medicare are funded by payroll taxes dedicated specifically to them. Some of the tax revenue pays for current benefits; anything that's left over goes into trust funds for the future. The programs were designed this way for political reasons.

The problem is that groups are only smart when the people in them are as independent as possible. This is the paradox of the wisdom of crowds.

You can't fuel real economic growth with indiscriminate credit. You can only fuel it with well-allocated, long-term investment.

As technology improves, on-screen avatars look more and more like real people. When they start looking too real, though, we pull away. These almost-humans aren't quite right; they look creepy, like zombies.