I want to second @amatsuuchi‘s encouragement re: teaching with Wikipedia. I have had really productive experiences assigning students to write Wikipedia in my classes.
At the undergraduate level there are four reasons why I have students write Wikipedia as a course assingment: 1. It is an empowering experience. Students are writing articles that will be in the top three search results for that subject. They are having a real impact in the world. 2. It is a great way to ensure that they are doing their research. All but one of my students responded in their self-evaluations that it was the most research they have ever done. They also recognized how much they learned, and said they enjoyed it. 3. The students were motivated because their work had a relevance outside the classroom, and was working for the greater good of society. Or to put it another way, they were introduced to service/volunteering. 4. Lastly, the way that the software tracks every edit, and the requirement that every statement be cited means that you have a better control over plagiarism, and can help students actually understand why they have to follow the rules. It also helps that many of the pages are regularly edited by other editors, who will remove items if they are not cited, or are clearly plagiarized; this happened in many cases. The best overview is in this blog post by the Wikimedia folks: http://blog.wikimedia.org/2012/01/04/design-professor-gives-students-real-world-experiences-through-wikipedia-assignment/ My undergraduate course is here, though it is a little messy: http://en.wikipedia.org/wiki/Wikipedia:Ambassadors/Courses/History_of_Design_and_Digital_Media_%28Michael_Mandiberg%29
I have also used it at the GC in PhD classes, where it is a great way to force these individual-minded scholars to collaborate. My assignment is here: http://2012core2.commons.gc.cuny.edu/2012/02/09/wikipedia-assignment/ At the graduate level, the challenges is that they are forced to work, collaboratively iteratively, and in public. Graduate students in the humanities are almost never allowed (let alone encouraged) to collaborate, and yet (I believe) collaboration is fundamentally important for any contemporary citizen & maker. They are also encouraged to work privately, hoarding their knowledge until a time when they make it public. Working in this way also helps them accept that ‘great is the enemy of good.’ Working collaboratively also forced an engagement with the social aspects of Wikipedia editing, leading to some substantial reflections on online communities. This comment thread (http://2012core2.commons.gc.cuny.edu/2012/02/29/learning-from-frustration/) is in the middle of a wikipedia edit conflict scenario, that the students ultimately resolved with the editor they are speaking about, and in the process learned a ton.
If any of you have any questions, I also would be happy to offer more on this forum, or speak directly. And as @amatsuuchi has pointed out, Richard Knipel is really the person to talk to. At the time I started I was comfortable doing basic edits, and could add photographs, but not much more; Richard and others helped me with some of the next level skills (talk pages, flagging pages, etc).