What's wrong is that perspective and style don't scale. Writing is hard even for the world's greatest wordsmiths; it requires time, thought, and care. Good writing also usually requires good editing. Because Wikipedia's NPOV guidelines set clear rules for what's allowed on the site, Wikipedia is easy to edit—anyone can look up the tenets of NPOV and then set about cleaning up contributions that stray from the preferred style.
By default, Knol articles can be edited by readers, but each edit must be accepted by the original author before the revision takes hold. Along with the obvious problem of giving authors control of when they're edited, Knol doesn't give readers any guidelines for how to edit. One Knol article on Tori Amos describes her 2007 album American Doll Posse as marking a return to "daring and somewhat angry" songs and adds that her voice on the record sounded better than it has "since 2001." Those lines are vague and mushy: What about the album is angry? Why does her voice sound so much better than before? Under Wikipedia's NPOV rules, both descriptions would have to go, and any reader could delete them with a couple of keystrokes. But Knol allows such personal opinions, so you'd have to persuade the writer to excise them on other grounds—which, of course, takes a lot of work. Instead of going through the trouble, I clicked away.
As I perused Knol over the past couple of weeks, I tried to contact the authors of the few articles that I found interesting. This proved difficult; Knol doesn't require writers to post their contact information. Even though readers are asked to accept these people as experts on a topic, there's no easy way to ask them questions about their expertise. Still, I did manage to contact a few Knol posters, and I was surprised by what I found: Most people who contributed to Knol did so for money.
Some authors wanted to test the power of Ad Sense, the text ads that Google lets writers place alongside their articles—Google gives authors a share of the revenue it generates from those ads. (People told me they hadn't earned more than a couple of dollars from these.)
Other authors were interested in promoting their Web businesses. Natasha Derrick, who runs a Web site called Hawaii Travel Guide with her husband, had repurposed several of her old pieces on Hawaii to post on Knol. (The Knol pieces include links to her Hawaii Travel Guide.) Derrick told me she hasn't seen any increase in traffic to her site yet. But she and her husband see Knol as a way to "get in on the ground floor" of something great. Knol could be the next Wikipedia, and Derrick's piece on the Hana Highway might make its way up the search rankings, delivering throngs of people to her site.
Derrick's plan dovetails nicely with Google's: If Knol is the next Wikipedia, both the writer and the company make a killing. The problem is that we don't need the next Wikipedia. Today's version works amazingly well.