I think Wikipedia should not be a major source in a student’s work, because it’s not a primary source. Like any encyclopedia it is a good place to get background information. Some articles have extensive citation and those citations can help students find good primary material for reports.
Fifth grade science teacher and I plan on setting up a science wiki for the fifth graders this year. I see no problem with having a login system that tracks changes and do not understand why purists would have a problem with it. Wikipedia after all track its changes and who has made them. We have consequences in place already for students who choose to vandalize another person’s work on or off line. Because our expectations are firmly in place I predict will have very little problems of the sort. Each class a students will be adding information to articles about topics mastered in science. They’ll also write a lab reports including both pictures and video of actual experiments. Science teacher will add review questions for tests, and students will add their answers for others to use. I’m also hoping that that fourth grade and maybe even third grade science teachers will be willing to do a similar project. Then each year the wiki to move up with the students. I’m not share if we will use the wiki in Moodle or if we will use www.wikispaces.com. I need to talk to the people in tech training about which would be better for a multiyear subject wiki.
I would love set up a curriculum wiki for my school. Getting teachers to communicate about what our students have difficulty with is an ongoing problem. I think because the teachers see it as a criticism of them, rather than an offer to help.