Knol: a unit of knowledge, is the latest beta offering from Google. It is a Wiki platform with new features, new posting rules and community tools. One major difference will be the inclusion of pay-per-click ad services.  According to the official Google Blog "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:"
On November 22, 2011, Google decided it was pulling the plug on seven projects, and Knol would be one of those. The decision by CEO Larry Page was "Spring Cleaning" to focus on fewer efforts.