Claim: Wikipedia had nearly 500 million visitors each month worldwide.

Wikipedia -LRB- -LSB- wɪkiˈpiːdiə -RSB- -RRB- is a free online encyclopedia with the aim to allow anyone to edit articles . Wikipedia is the largest and most popular general reference work on the Internet and is ranked among the ten most popular websites . Wikipedia is owned by the nonprofit Wikimedia Foundation .   Wikipedia was launched on January 15 , 2001 , by Jimmy Wales and Larry Sanger . Sanger coined Wikipedia , a portmanteau of wiki and encyclopedia . There was only the English language version initially , but it quickly developed similar versions in other languages , which differ in content and in editing practices . With articles , the English Wikipedia is the largest of the more than 290 Wikipedia encyclopedias . Overall , Wikipedia consists of more than 40 million articles in more than 250 different languages and , , it had 18 billion page views and nearly 500 million unique visitors each month .   As of March 2017 , Wikipedia has about forty thousand high-quality articles known as Featured Articles and Good Articles that cover vital topics . In 2005 , Nature published a peer review comparing 42 science articles from Encyclopædia Britannica and Wikipedia , and found that Wikipedia 's level of accuracy approached Encyclopædia Britannicas . Criticism of Wikipedia includes claims that it exhibits systemic bias , presents a mixture of `` truths , half truths , and some falsehoods '' , and that , in controversial topics , it is subject to manipulation and spin .