When I was in graduate school, my church group did some volunteering at a home for troubled kids. One week we colored Easter eggs with them. There were a bunch of kids and a bunch of eggs, so there was no individual ownership. While some kids in my group did some interesting things with eggs that were temporarily theirs, there was one boy who kept grabbing eggs and putting them in all the different dyes. So all our eggs ended up brown.
I have not used wikis in my classes, which tend to stress individual written and group oral work. Moodle has the advantage of having conversations between individuals, with people clearly responsible for their personal contributions. Maybe I will use wikis in the future. I didn't think I would ever use Blackboard (predecessor to Moodle), but along came a pedagogical problem and Blackboard was the answer. So maybe that will happen with wikis, too.
Note: Despite all the editors, Sara's class blog still has a sentence that reads "England controlled England," or something like that. I tried to edit it with my newfound wiki skills but it wouldn't let me.