Knowledge graph is occasionally used in place of ontology – an interlinked collection of entities describing real-world events, objects, situations as well as abstract concepts. However, since Google’s introduction of their knowledge graph data back in May 2012, the term frequently refers to the knowledge base used by the company to supplement search engine results using information collected from numerous sources.
This data is presented to searchers in a box next to the search results. With millions of entities and billions of facts, Google’s knowledge graph is able to answer approximately one-third of all search queries.
The information comes from a wide variety of sources including the CIA World Factbook, Wikidata, and Wikipedia. Although Google’s knowledge graph contains a great amount of factual information, it offers comparatively little in the way of formal semantics.
The knowledge panel is quite a prominent feature in search results. Not surprisingly, many online brands desire to obtain their own knowledge graph card.