A content graph is a knowledge graph that incorporates high value creative works as first class items within a graph. i.e. the graph does not just include metadata to annotate the content assets -with, it also includes and represents the content within the graph.
It depends on what you term as "content". The first large content graph at scale that included original editorial that is the main focus of the offering, and tied together by metadata and data, was BBC Sport in 2010 with the Winter Olympics. This pattern was then scaled up for the 2012 Olympics in London. At that time, the term "Content Graph", or indeed "knowledge graph" was not widely used.
Select a knowledge graph platform that supports media content publishing, including rich text, images, video, audio and whatever else you have planned. One example is the Data Graph Content Graph Platform .