Last December we wrote about Google Knol and now it is open for contributions. The difference between Knol and Wikipedia is that authorship is strongly encourages and every knol will be associated with an author or a group of set authors. Knol also favors multiple knolls on the same subject, allowing people to voice their opinion on a specific topic.
If there is an existing Knol on a topic and someone reading it wants to add or contribute to it, the author of that Knol can accept, reject or modify the suggested edit. A Knol can also include ads from Google Adsense, providing that author with a revenue share.
So far, I find Knol to be really easy to read and there are mostly articles about health related topics. Knol also allows you to include a biography about yourself to show your credibility in the particular subject you wrote about. This may become a great tool for businesses to be authoritative within Google about subjects that pertain to their business.
Check out Google Knol and see how you can contribute.