Last week Google announced an invite-only trial of a new tool called Knol (their name for a "unit of knowledge") to allow people to write an information page on a subject which can then be rated, reviewed or commented on by others. The central idea, as Google's VP of Engineering Udi Manber put it, is authorship:
"Books have authors' names right on the cover, news articles have bylines, scientific articles always have authors -- but somehow the web evolved without a strong standard to keep authors names highlighted. We believe that knowing who wrote what will significantly help users make better use of web content."
You can see a sample knol here (isn't everyone just itching to edit out that spelling mistake in the first sentence?).
Most of the press coverage of Knol is positing it as a competitor to Wikipedia, but is it really? We won't know what Knol will really be like until it is open to the public (presuming it makes it out of private beta), but from the looks of things it differs markedly from Wikipedia in all of the most important ways that Wikipedia is unique.
Firstly, knols won't be collaboratively written: Google says that the Knol platform will include "strong community tools", enabling the general unwashed to submit changes to knols (they use the name for individual articles too) as well as review, rate and comment on them, but ultimately the content of knols will be controlled by their original authors. Obviously, this is different from Wikipedia's collaborative wiki editing model under which no-one owns articles.
Secondly, there will likely be multiple knols on any given subject: as they say in the Knol announcement, it will be Google's job to appropriately rank knols in search results. Presumably they'll make use of the rating and reviewing tools in the platform as well as standard metrics like PageRank to try to work out which knol really is the most authoritative on a subject. Again, this is clearly different from Wikipedia, with its single-voice, neutral point of view system.
Thirdly, knols will not necessarily be free-content: while the sample knol mentioned above has a CC-BY 3.0 licence displayed on it, there are no indications that such licencing will be required, and Knol's "author control" vibe probably indicates that each author will get to choose the licence for their knols.
Kevin Newcomb at Search Engine Watch thinks a better comparison for Knol is Squidoo, and to an extent Mahalo, "since it allows users to build authority and sign their work [and aims] to build content pages that rank highly in search engines." Danny Sullivan at Search Engine Land also draws the comparison between Knol and Squidoo, and suggests that Knol is more likely an attempt by Google to carve out a niche of its own in the 'knowledge aggregation' industry rather than an effort to compete directly with any of the projects in the field.
However, it's perhaps best to think of the Knol proposal less as a project and more as a platform: Rafe Needleman at Webware compares Knol with Google's existing text publishing platform, Blogger, though with "Digg-like elements". Knol authors will build reputation, like blog authors (though Knol will be more about discrete articles rather than a stream of them), and users will rate and review competing knols in much the way that Digg and similar link-sharing sites operate. I think this is the best comparison, and fits well with the strong focus on individuality and authorship, and on Google's planned hands-off approach, in the Knol announcement. There's certainly a niche available for this kind of publishing.
So, presuming Knol goes public one day, it may well garner a significant slice of search results and a place in the knowledge business, but with its author-driven multiple-voice model and basis as essentially a publishing platform, it is more likely to be a complement to Wikipedia than a competitor.