There are several really good reasons why teachers should engage their students with Web 2.0 technologies, and among others, wikis.
In an excellent article called Using and creating knowledge with new technologies: a case for students-as-designers published in the March 2006 issue of Learning, Media and Technology, Kay Kimber and Claire Wyatt-Smith gives the following reasons:
1. Students are sophisticated users of technologies outside of school. Many students have access to technologies that are more powerful and sophisticated than the technologies they use in school. To address this issue, teachers have to be able to use more sophisticated and powerful technology tools IN school. The danger is that students will find schoolwork less challenging and interesting than their activities outside of school.
2. Another point to remember is that students predominantly use their powerful and sophisticated technologies for social communication. Thus, teachers have to be instrumental in ensuring that their students develop into critical, creative users of new technologies. To do this, teachers have to equip their students with tools and resources to argue, analyze, evaluate, interpret, and persuade. In other words, teachers have to help their students develop their capacities to build their knowledge and critically engage with material through the use of technology.
3. Now to the practical pedagogy: Establishing a community of learners is one of the best ways to engage students in the learning process. A learning community with shared experiences fosters a sense of belonging, the building of shared values, escalating intellectual engagement with material (being willing to tackle more difficult and more complex issues), and a safe place to build identity. You can read more about communities of learners in Edutopia.
4. Wikis are the most accessible venue for showing evolution of thought on any given subject discussed on a wiki. Most wikis have a HISTORY section that keeps track of different versions of the pages. Students and teachers can follow the increase in knowledge and sophistication of thought through this versioning capability.
5. Wikis make very good e-portfolios with ample opportunity for collection of intellectual products and reflection on those products.
6. Wikis are great venues for collaboration, based on the idea that our collective knowledge is more than the individual knowledge of each of us.
7. Wikis can help develop critical thinking skills - evaluating information, considering how to improve information, and producing collaborative thinking.
8. Wikis fit the emphasis on constructivist learning where people are producers, not just consumers of knowledge. According to Vygotsky, Piaget and Dewey, learning is a social activity.
8. Wikis are easy to use.
Wikis are free.
Wikis are dynamic content.
Resources:
Educause has a good 2 page booklet on 7 Things You Need To Know About Wikis.
Brian Housand and Kristina Ayers has a wiki on wikis: The Wonderful World of Wikis.