From an article in Wired on Wikipedia (hat tip to Peter Suber):
In the beginning, encyclopedias relied on the One Smart Guy model. In ancient Greece, Aristotle put pen to papyrus and single-handedly tried to record all the knowledge of his time. Four hundred years later, the Roman nobleman Pliny the Elder cranked out a 37-volume set of the day’s knowledge. The Chinese scholar Tu Yu wrote an encyclopedia in the ninth century. And in the 1700s, Diderot and a few pals (including Voltaire and Rousseau) took 29 years to create the Encyclopédie, ou Dictionnaire Raisonné des Sciences, des Arts et des Métiers.
With the Industrial Revolution, the One Smart Guy approach gradually gave way to the One Best Way model, which borrowed the principles of scientific management and the lessons of assembly lines. Encyclopædia Britannica pioneered this approach in Scotland and honed it to perfection. Large groups of experts, each performing a task on a detailed work chart under the direction of a manager, produced encyclopedias of enormous breadth. Late in the 20th century, computers changed encyclopedias – and the Internet changed them more. Today, Britannica and World Book still sell some 130-pound, $1,100, multivolume sets, but they earn most of their money from Internet subscriptions. Yet while the medium has shifted from atoms to bits, the production model – and therefore the product itself – has remained the same.
Now Wales has brought forth a third model – call it One for All. Instead of one really smart guy, Wikipedia draws on thousands of fairly smart guys and gals – because in the metamathematics of encyclopedias, 500 Kvarans equals one Pliny the Elder.
Instead of clearly delineated lines of authority, Wikipedia depends on radical decentralization and self-organization – open source in its purest form. Most encyclopedias start to fossilize the moment they’re printed on a page. But add Wiki software and some helping hands and you get something self-repairing and almost alive. A different production model creates a product that’s fluid, fast, fixable, and free.