Voice Thread is a free online tool that allows you to add comments to a photograph. I'm really excited about the possible uses for this--post a picture of a cell and have students leave comments explaining the different parts. Post a picture of a group and have each member leave a comment explaining how they contributed to the success of the group's work. Have students post a picture of who they would choose to star as the main character in a movie about a book, then have the class post comments about why they think this is a good choice, or who they would pick instead. I created a sample here just to show you how it works. This took about 10 minutes for me to get an account, upload my picture, get my microphone to work, and get this ready to share. Click here to go leave a comment. And have fun!