https://www.theguardian.com/technology/ ... economists
They also discovered something Graaf told us (over and over and over) for years: Dutch Wikipedia is very poorly managed, and run by the worst assholes imaginable. Not "news" around here.
But the structure of Wikipedia did provide one answer to the question: almost all the additions to the Dutch version of the site were removed within 24 hours, forcing the researchers to limit their examination of the effects to the other three languages.
A senior editor on the Dutch site had spotted the experiment in progress, and proceeded to ban all future updates from the team. Commercial editing is not allowed on the site, and the research was deemed to cross the line.