Indeed, the English-language version of the site had an estimated 38 million users in the United States in December and can be hard to avoid while on the Internet. Google searches on such diverse subjects as historical figures like Confucius and concepts like torture give the Wikipedia entry the first listing.

In some colleges, it has become common for professors to assign students to create work that appears on Wikipedia.

According to Wikipedia's list of school and university projects, this spring the University of East Anglia in England and Oberlin College in Ohio will have students edit articles on topics being taught in courses on the Middle East and ancient Rome.

In December 2005, a Columbia professor, Henry Smith, had the graduate students in his seminar create a Japanese bibliography project, posted on Wikipedia, to describe and analyze resources like libraries, reference books and newspapers. With 16 contributors, including the professor, the project comprises dozens of articles.

In evaluations after the class, the students said that creating an encyclopedia entry taught them discipline in writing and put them in contact with experts who improved their work and whom, in some cases, they were later able to interview.

"Most were positive about the experience, especially the training in writing encyclopedia articles, which all of them came to realize is not an easy matter," Smith wrote in an e-mail message. "Many also retained their initial ambivalence about Wikipedia itself."

The discussion raised by the Middlebury policy has been covered by student newspapers. The Middlebury Campus, the student weekly, included an opinion article last week by Chandler Koglmeier that accused the history department of introducing "the beginnings of censorship."

Other students call the move unnecessary. Keith Williams, a senior majoring in economics, said students "understand that Wikipedia is not a responsible source, that it hasn't been thoroughly vetted." Yet he said, "I personally use it all the time."

And yes, back at Wikipedia, the Jesuits are still credited as supporting the Shimabara Rebellion.