news of the day: Last week, global financial markets were churning, but it really only mattered if you were an oil trader, Chinese bureaucrat or hedge fund manager. Now it's starting to get scary for everyone. An 8.5 percent drop in the Shanghai Composite index in Monday's trading session spread to financial markets across the world. In the United States, the broad Standard & Poor's 500 index was down 2.5 percent in Monday morning trading, after steeper declines in Asian and European stock markets, falling prices for oil and other commodities, and a rush of money into the safety of U.S. Treasury bonds. What's fascinating is that there is no clear, simple story about what is different about the outlook for U.S. and European corporate profits; interest rates; or economic growth compared with one week ago, when the S&P 500 was 8 percent higher. Here's how to make sense of what is a truly global story, stretching from the streets of Shanghai, where stoc...