Google opened the doors for the public to the beta Knols. While Knols are very similar to Wikis there are two main overall design differences between the two. First of all while Wikis are “community authored” with a group of people behind most articles the Knols are author dependant. Whoever posts a Knol first becomes the author and moderator of the article. Secondly Knols have a direct interface to Google AdSense making it easy for the author to include ads in the articles, something few community based wikis allow (at least not to the benefit of the authors).
When writing Knols you have several options for each Knol you write (and by the way, Google defines “Knol” as a unit of Knowledge).
As an author you can choose to inlcude other authors or have an open (or moderated) author system much like the Wikis.
The information published in a Knol can be published under three different licenses that the author may choose from; “CC Attribution 3.0”, “CC Attribution-Noncommercial 3.0” and finally “All rights reserved”.
While I do not believe the wikis are in danger (and specifically the Wikipedia) the Knol does open up much more towards companies who might up until now found it pointless to give their information away for free. Being able to publish copyrighted material without losing control over it and at the same time gaining from AdSense published on those pages might interest some.