Google Introduces the Knowledge Graph

Google introduced the Knowledge Graph in May 2012 to supplement ordinary web search with structured information about real-world entities. Instead of treating every query as a collection of words, Google increasingly tried to determine whether a user meant a person, place, book, company, or other specific thing.

The graph connected entities through relationships: an actor could be linked to films, a city to a country, or a scientist to an institution. This let Google display facts directly beside search results and distinguish ambiguous names using context.

The change represented a shift from document retrieval toward semantic search. Ranking web pages remained essential, but search systems were increasingly building internal models of concepts and relationships rather than relying only on matching text strings.