13. The non-transitory computer readable medium of claim 11 , the operations further comprising: receiving user feedback based ratings for the first content; and generating a content rating for the first content that is proportional to a combination of the assigned initial content rating and the received user feedback based ratings.
11. A non-transitory computer readable medium storing instructions configured to cause one or more computers to perform operations comprising: receiving first content authored by a first author; determining that the first author has no assigned rating; and in response to determining that the first author has no assigned rating: identifying attributes of the first author; identifying other authors that are not authors of the first content, each other author having one or more attributes in common one or more identified attributes of the first author and not an author of the first content, and wherein at least one of the other authors has at least one attribute not in common with the first author; for each identified attribute of the first author in common with an attribute of one or more other authors, generating a rating for the identified attribute based on ratings that are assigned to the other authors having the attribute, the ratings that are assigned to other authors being based on user feedback; generating an initial content rating for the first content based on the ratings for the identified attributes; and assigning the initial content rating to the first content.