Those of you familiar with Voicethread understand how powerful it can be. Teachers can post a picture, video, slideshow, and more into Voicethread and students can add comments through text, recorded voice, or video. And it's all online so it can be accessed almost anywhere at any time.
Recently, they've added even more functionality to the commenting feature. You can now look through an entire collection of media files and make one single comment (in past versions you had to break things up and comment on each individual file).
To help make it as clear and easy as possible, watch the short video or visit their blog: