Wikidata: A Free Collaborative Knowledgebase


Denny Vrandečić, Markus Krötzsch

Wikidata: A Free Collaborative Knowledgebase

Abstract. Unnoticed by most of its readers, Wikipedia is currently undergoing dramatic changes, as its sister project Wikidata introduces a new multilingual ‘Wikipedia for data’ to manage the factual information of the popular online encyclopedia. With Wikipedia’s data becoming cleaned and integrated in a single location, opportunities arise for many new applications.

In this article, we provide an extended overview of Wikidata, including its essential design choices and data model. Based on up-to-date statistics, we discuss the project's development so far and outline interesting application areas for this new resource.

Published at Comm. ACM (Journal paper)

Download PDF (last update: March 11 2014)

Citation details

  • Denny Vrandečić, Markus Krötzsch. Wikidata: A Free Collaborative Knowledgebase. In Communications of the ACM 57:10, pp. 78–85. ACMProperty "Publisher" has a restricted application area and cannot be used as annotation property by a user. 2014.


As of March 2014, this is the main reference on Wikidata, thus finally answering the question "What to cite on Wikidata?" that many people have been asking for some time.

Thanks to Yusuke Matsubara, this article is now also a available in a Japanese translation ウィキデータ:共同作業で作られるフリーな知識ベース.


The article text is published under the terms of Creative Commons CC-By 3.0. The "appropriate credit" required by the license (the "By" part) should have the form of a citation of the article mentioning at least the authors, original title, journal, and year. The article is published under the ACMs hybrid open access model and will also remain freely available from ACM servers. Image copyrights are separate: Tower of Babel engraving by Isaac Basire of 1733 is out of copyright; the Reasonator screenshot (Fig. 3) includes media with various licenses and is considered Fair Use (Reasonator is created by Magnus Manske). The fonts used in the PDF are not free, we do not own any rights for them, and we do not release these fonts under CC-By.

Wikidata entity id

This article has subsequently received its own Wikidata item Q18507561, which can be used, e.g., within references on Wikidata.


We have entitled our paper "Wikidata: A free collaborative knowledge base," following the writing conventions of our field of research. The rather uncommon spelling "knowledgebase" (without a space) was chosen by the copy editors against our advice. However, this is how the world's citation databases list the article now.


Semantic wikis, Semantic Web, Wikidata