The difficult question is how will Newark turn the privately owned, illiquid shares of Facebook into usable cash for their troubled school system?

FORBES: How Will Newark Turn Zuckerberg's $100 Million Worth Of Facebook Shares Into Cash?

When faced with planning a new data center the question of how much space will be needed is potentially the most difficult to determine.

FORBES: The Case for the Infinite Data Center

One, admittedly very difficult, question is how to charge market prices for energy to those who can afford them, while protecting the really poor from freezing in winter.

ECONOMIST: Russia��s infrastructure