You can use the Wiki tool to help create study guides for your class. This tool works a lot like Wikipedia.org, where any user can add and edit information to the pages. With this tool, you can have your students build and edit study guides with items like terms, dates, formulas, and more.
Each student can contribute valuable information and easily share it with classmates. For example, you may want to personally assign students specific sections of the study guide.
Since wikis do provide an optional grading feature, you may want to use wikis as an assignment for a class participation grade. How often students contribute to the wiki will reflect in their overall Class Participation rating. Read more
There is a Page History area where you can view the different edited versions of a specific wiki, the date the version was created, the size of the editing, and the user who had created an updated version of the wiki. You can get to this page by clicking the double-down arrows to the right-hand side of the wiki and selecting on History.
Although the Wiki tool will not prevent a student's ability to sell study guides, it will be a deterrent since it offers a constructive way for students to prepare for their test together.