Here's Wikipedia's definition of a wiki.

Check out the overview of wikis at Teachers First's Wiki Walk-Through

Technology Teacher features a good article on 10 Best Practices for Using Wikis in Education.

Feel free to use or modify these rubrics for grading wikis: external image pdf.png WikiGradingRubric.pdf and external image pdf.png wikirubric.pdf

Trying to decide whether or not to use a particular wiki for research? Check this out: external image msword.png Evaluating Wikis.doc