Discovering relevant concept and context for content node

An apparatus comprising:

• memory comprising a concept association map that represents concepts, concept metadata, and relationships between the concepts, wherein such a map is dynamic and constantly updated, wherein the results on the concept association map are clustered, wherein the content nodes are tagged with labels that represents at least one high level category;
• and
• a processor comprising:
• a candidate concept extractor configured to extract one or more concept candidates from a content node based on a match of concepts in a concept association map against text in the content node;
• a filterer configured to rank the one or more concept candidates to create a ranked one or more concept candidates based at least in part on a measure of relevance after the candidate concept extractor extracts the one or more concept candidates in the content node;
• and
• a concept expander configured to expand the ranked one or more concept candidates according to one or more cost functions, wherein an expanded set of concepts is created after the concept filterer ranks the one or more concept candidates, wherein
• the apparatus is further configured to store the expanded set of concepts in association with the content node in the memory.