For the past 15 years, Wikipedia has informed and misinformed* nearly a generation of internet users about history, science, popular culture, and pretty much everything else on Earth. The are articles on broad topics, as well as extremely narrow ones. Some of those are very controversial and the editors debate vigorously over what precisely is the truth and what constitutes objective descriptions of it.
This past January, Five Thirty-Eight, Nate Silver's popular statistics blog, created this chart illustrating the three most heavily edited articles for every year of Wikipedia's existence. Rapidly changing events, like the 2011 earthquake and tsunami in Japan, and political controversies are obvious picks. But I'm baffled as to why 2009 was a peak year for the Chevrolet Vega and the article on Japanese dissidence during the Shōwa period was revised so often during 2014.
-via Jonah Goldberg
*I'm a college librarian, so I spent way too much time explaining to students why it's not acceptable to use Wikipedia as a source of information in their research assignments.