Freebase (knowledge base)
Open collaborative knowledge base launched in 2007 by Metaweb, acquired by Google in 2010, and shut down in 2016 after its data was partially migrated to Wikidata. A direct conceptual ancestor of modern public knowledge graphs.
Freebase was a large, openly editable knowledge base of structured data about real-world entities — people, places, films, works, organizations, and abstract concepts — modeled as a graph of typed nodes connected by relationships. It was developed by Metaweb Technologies, a San Francisco startup, and launched publicly in March 2007 with an HTTP API and its own JSON-based query language, the Metaweb Query Language (MQL). Google acquired Metaweb in July 2010, citing Freebase as a way to help search engines understand entities rather than strings. Freebase became one of the early seed datasets for the Google Knowledge Graph, announced in 2012. By January 2014 the database held roughly 44 million topics and 2.4 billion facts. On 16 December 2014, Google announced that Freebase would be retired in favor of Wikidata and that it would help port content across. The read/write API was closed in mid-2015, and the service was fully shut down on 2 May 2016. The Freebase data dumps remain available as historical snapshots, and a portion of its content was loaded into Wikidata via the Primary Sources Tool, though structural differences (Freebase's type system, compound value types, and looser sourcing norms) made the migration partial rather than wholesale. Freebase is often cited as the direct ancestor of contemporary open knowledge graphs and is still referenced in machine-learning research datasets (for example FB15k) used to benchmark knowledge graph embedding models.