Knol is Google’s answer to Wikipedia.

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.