One point that I had from experience is that Wikipedia tends to entrench the bias of its editors, through seemingly sensible policies. A specific example happened to me while contributing to the Arab spring pages (while the Arab spring was ongoing). It was claimed that the Tunisian revolution was the first by an Arab country. I disagreed because Sudan had a couple, which I know of because I am Sudanese. Sensibly, the admins requested citation needed and no original research. Given that the statement in question was mentioned in the NYT and the British Guardian. I had to contact the journals, and the Guardian actually published a correction, before the issue was settled. For other issues involving Sudan I was generally not so lucky. Wikipedia reflects the US understanding of Sudan, with a European slant, much more than it reflects the situation in Sudan.

My lesson: we must try to understand the New York Times effect on man..