This week's story that no one read and everyone should have is about tortilla riots in Mexico. Yes, tortilla riots. In Mexico. Some 75,000 people protesting the rising price of tortillas.

Not to be overly blunt, but who cares, right? It's just a single grocery item in some other country. But the reason the people are up in arms is more important than anyone realizes.

Poor Mexicans rely on tortillas for their diet. And a lot of other poor people in a lot of other places rely on other foodstuffs made from corn.

The problem is ethanol. Ethanol, that fuel additive that reduces pollution and helps us wean our dependency on foreign oil and makes farmers rich and politicians look silly when they stump in Iowa. As the U.S. adds more ethanol to its gasoline, the price of corn is surging dramatically, leading to extreme market volatility.

President Bush wants to use a variety of sources to make ethanol as the government pushes increased use of the additive, but for now most U.S. producers seem to be eschewing sugar and other products in favor of corn. If that remains the case, corn prices will only go higher and the poor of Mexico and elsewhere will be further pinched.

Of course, publicly-traded corn companies like Archer-Daniels-Midland (NYSE: ADM), Bunge Ltd. (NYSE: BG) and Corn Products International Inc. (NYSE: CPO) can't and don't mind that much - their profits are soaring. Big multinationals like Wal-Mart Stores (NYSE: WMT) must be happy too -- higher prices on big-selling staples are always a happy thing.