It has been a long time coming, and the subject of much online speculation as a result, but now Google has finally officially launched Knol. Google seems to be positioning this as less alternative to, and more complimentary with, Wikipedia.

"Knols are authoritative articles about specific topics" Google says "written by people who know about those subjects."

Which sounds very much like Wikipedia, apart from the 'people who know about those subjects' bit in many cases of course. He says, tongue planted only partially in cheek. So what is the difference? Over to Google again:

"An enormous amount of information resides in people's heads: millions of people know useful things and billions more could benefit from that knowledge. Knol will encourage these people to contribute their knowledge online and make it accessible to everyone."

Right, that still sounds an awful lot like Wikipedia to me. The real difference is that Knol will not rely upon the wisdom of crowds but rather the wisdom of the individual. "The key principle behind Knol is authorship" Google insists, adding "Every knol will have an author (or group of authors) who put their name behind their content. It's their knol, their voice, their opinion."

There will, of course, be multiple Knols covering the same subject matter as a direct result of this approach. But Google is not phased by this and actually sees the multiplicity as a good thing. Although there will be a moderated collaboration option to allow the original author to accept suggested edits from others, this is entirely optional and as the name suggest entirely at the whim and under control of the original author.

Not under that control is the ability for the community to submit comments, reviews and ratings. This, combined with the Google search system allowing the cream to rise naturally to the top will, Google hopes, sort the knowledgeable wheat from the dimwit chancer chaff.

This is not the only thing that differentiates Knol from Wikipedia, however, there is the small matter of money. While anyone can publish a piece for inclusion in the Knol body of work, just as anyone can do the same at Wikipedia, Google is offering an AdSense incentive.

Authors can opt to include advertising and share any revenue generated from visitors with Google itself.