14. The method of claim 11 , wherein the plurality of tag chains are specified by different types of users, wherein the metric is at least partly based on a particular type of user that specified the particular tag chain in the plurality of tag chains.
14. The method of claim 11 , wherein the plurality of tag chains are specified by different types of users, wherein the metric is at least partly based on a particular type of user that specified the particular tag chain in the plurality of tag chains. 15. The method of claim 14 , wherein the different types of users includes at least one of a content provider, a content retriever, and a content evaluator.