Teaching in the the World of Wikipedia

Inside Higher Ed reports that the history department at Middlebury College has begun to prohibit students from citing Wikipedia in papers they write for class. This strikes me as an important issue for English educators because we not only set policies about research and writing practices for our own classes, we also teach about appropriate practices for writing from sources in high school. How do you approach Wikipedia? How about other online sources? Is it enough if students properly "cite the site" or should we be doing more to, in the words of the Middlebury history department chair, "[reduce] the dissemination of misinformation?"