The value of a currency is, ultimately, what someone will give you for it - whether in food, fuel, assets, or labor. And that's always and everywhere a subjective decision.

Solyndra's failure isn't a reason for the government to give up on alternative energy, any more than the failure of Pets.com during the Internet bubble means that venture capital should steer clear of tech projects.

Self-dealing, essentially, occurs when managers run companies to line their own pockets instead of those of the companies' owners. It's been a perennial problem in American capitalism and became a real dilemma when America moved toward a model in which corporations would be run by professional managers who had only small ownership stakes.

Political risk is hard to manage because so much comes down to the personal choices of policymakers, whether prime ministers or heads of central banks.

On the simplest level, telecommuting makes it harder for people to have the kinds of informal interactions that are crucial to the way knowledge moves through an organization. The role that hallway chat plays in driving new ideas has become a cliche of business writing, but that doesn't make it less true.

In a world where companies increasingly know about their business in real time, it makes no sense that public reporting mostly follows the old quarterly schedule. Companies sit on vital information until reporting day, at which point the market goes crazy.

The oil market is especially sensitive even to a hint of expansion or contraction in supply.