Schools/colleges banned Wikipedia use in 2007-2008
In 1995-2005 educators were enthusiastic about the Internet as an exotic new environment. Then in the current era 2005-2015, when several projects (Wikipedia, Google Book Search, Google Maps, ...) have started to actually fill this new environment with real, useful knowledge, educators are worried that knowledge is too easy to find, far easier than in traditional libraries, and sometimes not as well researched. When students come back with term papers citing Wikipedia, the teachers' reaction is to ban Wikipedia. But the students didn't go to Wikipedia, they went to Google and Google returned the best of the web. So next time, students will go to Google and pick the second best of the web, because that website is not banned by teachers. How long will it take before teachers start to understand the web and Wikipedia's role within the web? A full decade?
What is the average age of teachers? When the current cohort of young Wikipedia users grows up, some of them will be teachers. Then they will encourage their students to use Wikipedia, and try to ban whatever has come after Wikipedia. The purpose of adults is to delay progress.