Freebase Knowledge Base

Context:
- It can have a Freebase Schema, which:
  - can (typically) contain Freebase Entitys (including lexical names).
  - can (typically) contain Freebase Relations (in the form of <arg1, relation, arg2> triples).
- It can be accessed by a Freebase System.
- It can (typically) be a Stale KB.
- …
Example(s):
- https://developers.google.com/freebase/data
- http://aws.amazon.com/datasets/8247878934976180
- vX
  - w/ 20M Freebase Entity, and w/ 10K Freebase Relations.
  - and 637M Facts
Counter-Example(s):
- Wikidata KB.
- DBpedia KB.
- Yago Knowledge Base.
- Google Knowledge Graph.
- a Wikipedia Data Snapshot.
- a CyCorp Database.
See: Metaweb, Triple Store.

References

http://wiki.freebase.com/wiki/MQL
- On 16 December 2014, the Freebase team officially announced^[1] that the website and the application programming interface would be shut down by 30 June 2015. Google provided an update on 16 December 2015 that they will discontinue the Freebase API and widget 3 months after a Suggest widget replacement is launched in early 2016.

(Wikipedia, 2016) ⇒ https://en.wikipedia.org/wiki/Freebase#Discontinuation Retrieved:2016-5-23.
(Wikipedia, 2016) ⇒ https://en.wikipedia.org/wiki/freebase Retrieved:2016-5-23.
- Freebase was a large collaborative knowledge base consisting of data composed mainly by its community members. It was an online collection of structured data harvested from many sources, including individual, user-submitted wiki contributions. Freebase aimed to create a global resource that allowed people (and machines) to access common information more effectively. It was developed by the American software company Metaweb and ran publicly since March 2007. Metaweb was acquired by Google in a private sale announced 16 July 2010. Google's Knowledge Graph was powered in part by Freebase. Freebase data was available for commercial and non-commercial use under a Creative Commons Attribution License, and an open API, RDF endpoint, and a database dump was provided for programmers. On 16 December 2014, Knowledge Graph announced that it would shut down Freebase over the succeeding six months and help with the move of the data from Freebase to Wikidata. On 16 December 2015, Google officially announced the Knowledge Graph API, which is meant to be a replacement to the Freebase API. Freebase.com was officially shut down on 2 May 2016.

http://wiki.freebase.com/wiki/What_is_Freebase%3F
- Freebase has information about approximately 20 million Topics or Entities at the time of writing. Each one has a unique Id, which can help distinguish multiple entities which have similar names, such as Henry Ford the industrialist vs Henry Ford the footballer.
  Most of our topics are associated with one or more types (such as people, places, books, films, etc) and may have additional properties like "date of birth" for a person or latitude and longitude for a location. These types and properties and related concepts are called Schema.
  Anyone can contribute data to Freebase, and you can also build your own schema in a Base if Freebase does not yet have schema for a subject you're interested in.

http://wiki.freebase.com/wiki/Graph
- Freebase is a graph database. This means that instead of using tables and keys found in conventional database to define data structures, Freebase defines its data structure as a set of nodes and a set of links that establish relationships between the nodes. Because its data structure is non-hierarchical, Freebase can model much more complex relationships between individual elements than a conventional database, and is open for users to enter new objects and relationships into the underlying graph. See also: Graphd

(Bollacker et al., 2008) ⇒ Kurt Bollacker, Colin Evans, Praveen Paritosh, Tim Sturge, and Jamie Taylor. (2008). “Freebase: A collaboratively created graph database for structuring human knowledge.” In: Proceedings of the 2008 ACM SIGMOD International Conference on Management of data (SIGMOD 2008) doi:10.1145/1376616.1376746