What can wikis be used for in education?...anything that is paper in a classroom, could be converted to a wiki. Group projects, class collaboration and problem based learning can be facilitated by wikis.
In one article I read the students used a wiki and worked in groups to solve problems. They also posted pages for test reviews that were well done. These are younger children but they understand and grasp how to use these tools very well.
I think that in general wikis, blogs, etc. are plug and play. We should ask what are our needs in learning and education? Then we look at all the tools out there, whether it be a wiki or blog etc. and evaluate whether it is a good solution or not. What needs are there for web pages focused on certain topics and have the capalility to vote on content, to be edited, searched, and tagged? Whatever needs we may have for a tool with those specifications a viable solution could be a wiki. Will that be the case in 5 years, perhaps not.
I can imagine very easily a social issue that needs to be analyzed using knowledge of a discipline, say creative energy sources and biology. The problem could be posted on a wiki with some structure to the site and then the students would research, dig, learn, write and check the work of each other.
By no means should we force the use of technology just for technology's sake in education.