Instagram is now going to start adding a 5 second photo or 15 second video add between stories where there is more than on in a row. They will be set to autoplay with audio. Users will have the ability to skip by swiping.
Instagram is boasting over 150 million users are now using stories. You should start to see ads soon as they are currently testing with larger brand names.
Instagram Stories are alike Snapchat stories where users can share photos and videos in a separate stream where the posts disappear after 24 hours. Stories are found at the top of the stream with user profile images in a circle.