Summary
Moodle offers several options for students to collaborate on building a body of knowledge. A class can work together to build a glossary, which can be imported and reused in future classes. They can work together to write a wiki, which provides an opportunity for them to organize their knowledge into a narrative.
Look at glossaries as a way for students to collect new knowledge, and look at wikis as a way for students to organize new knowledge. Monitor these activities and encourage your students to participate.