Wikipedia

Wikipedia is a free online encyclopedia that anyone can edit, launched on January 15, 2001 by Jimmy Wales and Larry Sanger as a complement to the editor-reviewed Nupedia project. Articles are produced collaboratively by volunteers and published under the Creative Commons Attribution-ShareAlike license, making the entire corpus reusable for any purpose including commercial use and machine learning. Editorial governance rests on three core content policies: a neutral point of view, verifiability (claims must be sourced to reliable secondary publications), and no original research. Disputes are resolved through talk-page discussion, arbitration committees, and — for persistent vandalism or edit wars — semi-protection or full protection of articles. The Wikimedia Foundation, a US 501(c)(3) nonprofit headquartered in San Francisco, hosts the servers and handles legal/fundraising functions but does not control content. Scale figures (as of 2026): more than 6.8 million articles in English alone, over 300 active language editions, roughly 280,000 active monthly editors across all projects, and tens of billions of monthly pageviews. The English edition averages over 100,000 edits per day. The full text dump is a few tens of gigabytes uncompressed. Wikipedia's significance extends well beyond direct readership. Empirical studies (Thompson & Hanley 2018; Vincent & Hecht 2021) document its role in shaping scientific literature, search engine results, and AI training corpora — Wikipedia is heavily upsampled in datasets like C4 (Colossal Clean Crawled Corpus) and the GPT family's training mix. This makes it a load-bearing component of the modern information ecosystem despite being maintained almost entirely by unpaid volunteers. Persistent criticisms include systemic bias in editor demographics (skewed male, Global North), gender gaps in biographical coverage, vulnerability to coordinated editing campaigns, and uneven quality across topics — technical articles tend to be strong, while obscure biographies and recent events can be unreliable. The encyclopedia is generally considered acceptable as a starting reference but not as a citable source in academic work, although the line between reading-Wikipedia-first and citing-Wikipedia has blurred over time.