1. A computing apparatus comprising: a processor; and a content management service to be operated on the processor to: receive a plurality of content rules, each of the content rules specifying one or more criteria for application of the content rule to one or more instances of content of a plurality of instances of content; identify one or more instances of content that match the criteria specified by one or more of the plurality of content rules; and apply the one or more of the plurality of content rules to the corresponding identified one or more instances of content in a hierarchical manner based on a specificity of the criteria, wherein a rule specifying more specific criteria is applied with priority over a rule specifying less specific criteria, and wherein respective content metadata of the corresponding identified one or more instances of content is annotated with the one or more plurality of the rules.