VoiceThread is an asynchronous tool used to foster communication between teachers and their students. The creator of the VoiceThread provides media to have a conversation about and those who view it can comment on that media in a multitude of different ways. Examples of media that you can share are Word documents, Power Point slides, video files, and photos, just to name a few. VoiceThread also integrates easily with Moodle courses making a VoiceThread component possible in courses.
Check out the following videos to get started using VoiceThread: VoiceThread Tutorials