Wikipedia (pronounced as either [ˌwiˑkipidi.ə] or [ˌwɪki pidi.ə]) is a multilingual, Web-based, free-content encyclopedia. It is written collaboratively by volunteers with wiki software, meaning articles can be added or changed by nearly anyone. The project began on January 15, 2001 as a complement to the expert-written Nupedia, and is now operated by the non-profit Wikimedia Foundation. The English-language version of Wikipedia currently has over 790,000 articles. Wikipedia has steadily risen in popularity, and has spawned several sister projects, such as Wiktionary, Wikibooks, and Wikinews. Articles in Wikipedia are regularly cited by the mass media and academia, who praise it for its free distribution, editing, and diverse range of coverage. Editors are encouraged to uphold a policy of - neutral point of view under which notable perspectives are summarized without an attempt to determine an objective truth. Yet due to its open nature, vandalism and inaccuracy are constant problems — and the status of Wikipedia as reference work has been controversial. It has also been criticised for systemic bias, preference of consensus to credentials, and a perceived lack of accountability and authority when compared with traditional encyclopedias. There are about 200 language editions of Wikipedia (about 100 of which are active). Ten editions have more than 50,000 articles each: English, German, French, Japanese, Italian, Polish, Swedish, Dutch, Portuguese, and Spanish. Its German-language edition has been distributed on compact discs, and many of its other editions are mirrored or have been forked by websites.
