Following a restricted beta which began last December, Google has made its Wikipedia competitor Knol open for general use. While Knol borrows the general concept of "anyone can contribute" common to most wiki projects, it has a slight twist, as Google's software engineers explain:
With Knol, we are introducing a new method for authors to work together that we call "moderated collaboration." With this feature, any reader can make suggested edits to a knol which the author may then choose to accept, reject, or modify before these contributions become visible to the public. This allows authors to accept suggestions from everyone in the world while remaining in control of their content. After all, their name is associated with it!