Knol is open to everyone

Google announced it's new product: Knol.Knol is a place that people can write authoritative articles about topics, one of the differences between Knol and services like Wikipedia is authorship. 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. so a single topic can have several knols.(as knol says that's good a thing).
It has community features as well: Your readers will be able to add comments and rate your article, and, if you want, they'll be able to suggest edits that you can then either accept or reject(moderated collaboration). And, just like in Blogger, you can also choose to include ads from AdSense in your knols to perhaps make a little money.
From here & here