Wikipedia's closely-examined editing community has been declining for quite some time, and historian and Wikipedia editor Richard Jensen has a theory that may explain why. The problem, Jensen postulates, is that there's simply less work for editors to do than there has been in the past. He cites the editing histories of popular articles like the War of 1812 and World War II, which peak between 2005 and 2007. In contrast, the articles' pageviews have steadily increased, which Jensen says shows that there isn't a lack of engagement, but rather that popular articles are nearly complete. Take a look at more highlights from Jensen's study at The Atlantic.
[Source: The Verge]