Smart Alerts isn't the only Galaxy S III feature that you can get on other devices. Pop Up Play, which is the S III's ability to take a video and move it into a separate window on top of the rest of the OS, is also possible on other devices. The app you use is called Stick It! and it allows you to play videos in a tiny window on the screen.
The app has some issues, specifically lack of proper hardware decoding for video causing it to use software decoding instead ( = slow), and it also isn't bug free. For $1.50 though I think it's a neat app.
PS: The video above shows a black box where the video is. This is caused by the screen recorder app and on the actual screen it showed the video just fine.