TinEye is a great reverse image search online service, that can tell you where an image came from, find different sizes of the image and you can find out if someone is using your image without your permission.
If you know how to sing or hum a song, but don't know the title or the artist performing it, you can use a midomi website which will help you find the the song.
Let me show you a very simple yet effective trick that will stop the ads from popping up when you or your kids are playing iPad games. It can save you some money as well.