This New Yorker article nails Wikipedia's appeal.

Apparently, no traditional encyclopedia has ever suspected that someone might wonder about Sudoku or about Prostitution in China. Or, for that matter, about Capgras delusion (the unnerving sensation that an impostor is sitting in for a close relative), the Boston molasses disaster, the Rhinoceros Party of Canada, Bill Gates’s house, the forty-five-minute Anglo-Zanzibar War, or Islam in Iceland. Wikipedia includes fine entries on Kafka and the War of the Spanish Succession, and also a complete guide to the ships of the U.S. Navy, a definition of Philadelphia cheesesteak, a masterly page on Scrabble, a list of historical cats (celebrity cats, a cat millionaire, the first feline to circumnavigate Australia), a survey of invented expletives in fiction (“bippie,” “cakesniffer,” “furgle”), instructions for curing hiccups, and an article that describes, with schematic diagrams, how to build a stove from a discarded soda can.

That's the bloggiest part, but it's a great article all around:

Wattenberg and Viégas, of I.B.M., note that the vast majority of Wikipedia edits consist of deletions and additions rather than of attempts to reorder paragraphs or to shape an entry as a whole, and they believe that Wikipedia's twenty-five-line editing window deserves some of the blame. It is difficult to craft an article in its entirety when reading it piecemeal, and, given Wikipedians’ obsession with racking up edits, simple fixes often take priority over more complex edits. Wattenberg and Viégas have also identified a “first-mover advantage”: the initial contributor to an article often sets the tone, and that person is rarely a Macaulay or a Johnson. The over-all effect is jittery, the textual equivalent of a film shot with a handheld camera.

What can be said for an encyclopedia that is sometimes right, sometimes wrong, and sometimes illiterate? When I showed the Harvard philosopher Hilary Putnam his entry, he was surprised to find it as good as the one in the Stanford Encyclopedia of Philosophy. He was flabbergasted when he learned how Wikipedia worked. "Obviously, this was the work of experts," he said. In the nineteen-sixties, William F. Buckley, Jr., said that he would sooner “live in a society governed by the first two thousand names in the Boston telephone directory than in a society governed by the two thousand faculty members of Harvard University.” On Wikipedia, he might finally have his wish. How was his page? Essentially on target, he said. All the same, Buckley added, he would prefer that those anonymous two thousand souls govern, and leave the encyclopedia writing to the experts.