Collaborative learning, there are so many different web2.o tools that support students collaborating together in order to learn. I have used etherpad a number of times and the students really enjoy it. While I'm a Moodle advocate, that does not mean I limit myself to Moodle activities. There is nothing stopping you adding a link on your Moodle page that then takes students to another web activity. For a really nice example of how a teacher has utilised Etherpad for collaborative learning check this link out.