A knol is an authoritative article about a specific topic.
From Google: “A few months ago we announced that we were testing a new product called Knol. Knols are authoritative articles about specific topics, written by people who know about those subjects. Today, we’re making Knol available to everyone.
The web contains vast amounts of information, but not everything worth knowing is on the web. An enormous amount of information resides in people’s heads: millions of people know useful things and billions more could benefit from that knowledge. Knol will encourage these people to contribute their knowledge online and make it accessible to everyone.
The key principle behind Knol 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. We expect that there will be multiple knols on the same subject, and we think that is good.”
Hat tip to beSpacific.com