Royal Dutch Shell is one of the world’s largest and most powerful corporations. Bolivia is one of the planet’s poorest countries; its economy is a mere 3 percent of Shell’s annual revenues. Recently, Shell CEO Jeroen van der Veer noted, somewhat meekly, that his company was resigned to accept Bolivia’s decision to break the contracts it had signed.

Further, he said, it was no longer a good idea for oil companies to put up a legal fight against the nationalistic policies of countries like Bolivia. Once upon a time, giant multinational corporations did not bend to the will of tiny governments. The behemoths of industry did not just stand by as their oil, gas, or mining fields were seized under a national banner. They fought back, and not just rhetorically.

In another part of the world, a ragtag militia equipped with small arms and improvised explosive devices is denying the most powerful military in history control of the territory it swiftly conquered. This same pattern, in which small “micropowers” are successfully contesting the dominion of traditional “megaplayers,” is also in evidence in a far more cerebral market: encyclopedias. The survival of the world’s oldest and most respected source of information, The Encyclopaedia Britannica, is threatened by strange newcomers. One of them, Wikipedia, though just five years old, is already 12 times larger than the Britannica that sits on your bookshelf. Wikipedia is free, exists only on the Web, can be read in 229 languages, and is expanded daily by unpaid volunteers. A recent study published in Nature magazine found in a random sample of entries that, despite its far larger size, Wikipedia had 162 errors, whereas Britannica had 123.

Britannica is not, of course, the only business whose...