You really wouldn't have any idea what a "knol" is, by the looks of it they've just invented it over at the Mountain View headquarters. It stands for "unit of knowledge" and it is a free tool that is right now being tested by a select few, and that has as its goal to encourage people who know a lot about a particular subject to write an authoritative article about it.

Udi Manber, VP Engineering further explains the tool: "The key idea behind the knol project is to highlight authors. 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. At the heart, a knol is just a web page; we use the word 'knol' as the name of the project and as an instance of an article interchangeably. It is well-organized, nicely presented, and has a distinct look and feel, but it is still just a web page. Google will provide easy-to-use tools for writing, editing, and so on, and it will provide free hosting of the content. Writers only need to write; we'll do the rest", he says.

From what I understand, they are trying to build something similar to Wikipedia, but that will also include ads, if the writer so wishes, ads that will provide him with substantial revenue. The knol will be the first thing that will pop up when a person searches for that particular topic the knol is about. However, despite the many tools it will provide the authors, Google will not serve as an editor in any way and will not bless any content, all of that belonging to the author and he would be well in his rights to even delete it, if he so chooses to.