Google Knol is one of the many projects being killed by Google. The company has now made available a simple migration tool and you can use it to move all your content to WordPress.com.
The content would be switched to a customized WordPress blog running Annotum open source platform.
Google spoke about the project:
Knol will be discontinued as a service, but we’ve worked with Solvitor and Crowd Favorite to create Annotum, an open-source platform based upon WordPress that allows you to continue authoring and publishing scholarly articles. You can migrate your knols to WordPress and continue your work with Annotum. After May 1, you will no longer be able to create, view, enter or edit knols, but you will be able to export your knols to WordPress.com and download them to file through October 1st, 2012.