Reading some of the blog posts on Google's Knol, I'm surprised there isn't more talk about attribution. To me, the really interesting difference between Knol and Wikipedia is the way they handle attribution. In Wikipedia, attribution is deeply submerged. Articles aren't attributed to individuals. Edits are attributed, but even they are attributed via pseudonym. All of that is, of course, consistent with Wikipedia's Creative Commons philosophy. The whole idea is to de-emphasize individual ownership in the service a shared communal resource. That may be why Wikipedia converts only a tiny percentage of its readers into writers. People contribute to Wikipedia either because they are passionate about sharing knowledge, or because they are sufficiently plugged into the Wikipedia community that recognition in that community is itself an incentive. That's a relatively small group of people in relative terms, but fortunately for the rest of us the Internet is sufficiently large that it's big enough to maintain a pretty fantastic resource.
Google is trying to attract a completely different type of contributor: a self-interested one. Google is betting that there are a lot of people who would contribute to resources like Wikipedia if only they got more personal recognition for it. By putting attribution front and center, Google is providing that recognition.
If the number of personal blogs on the Internet is any indication, Google's strategy will generate a lot of participation. Public blogging has shown us (in case we needed to be shown) that there are a lot people who like to see their views in print. That's the motivation that Google is trying to tap into it.
But all that participation will come at a price. Wikipedia's quality is high precisely because there is a core community that cares deeply about it and ensures that crap is detected and eliminated. Google Knol isn't likely to generate that kind of committed community. As a result, it will probably come to look more like the blogosphere: Tons of content, some good, a lot of crap.
Google's solution to the quality problem is, predictably, technology. Feedback ratings are a central feature of Knol's design, and Google is almost certainly working on search algorithms that incorporate user ratings, not just at the asset level (i.e., article quality) but also at the author level (i.e., personal reputation).
Will Google's self-interest-plus-technology model trump Wikipedia's community model? It's hard to say a priori, so for now I'm just going to watch what happens. It will certainly be interesting.