For years now at our large college we’ve been trying to encourage teachers to use more of the collaborative aspects of Moodle, with little success. Chat rooms become venues for random chatter and forums remain stubbornly unused. We have also promoted all manner of Web 2.0 services, including subscribing to the old classic voicethread, but with limited success.
Recently though a few teachers have used Padlet for getting quick feedback on simple questions. The main advantage being the accessibility of use and the fact that once you have the Pad set up users need no login to participate. Here’s an example from @eleniZazani