53. The system of claim 49 , wherein determining if the first metadata item is relevant to the content object comprises: generating a relevance score based upon a similarity of the first metadata item to the content object, wherein the first metadata item is relevant to the content object in response to the relevance score being at least a threshold value.
53. The system of claim 49 , wherein determining if the first metadata item is relevant to the content object comprises: generating a relevance score based upon a similarity of the first metadata item to the content object, wherein the first metadata item is relevant to the content object in response to the relevance score being at least a threshold value. 54. The system of claim 53 , wherein the threshold value is based upon a type of the activity history.