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.
You are preparing a world wide event in your city and you want to be sure that every person around the world will know the exact time in their city. You will find out how in this tutorial.
Great website where you enter your iPhone or Android phone's IMEI and find out when your repair and service warranty is due and whether your device is locked on unlocked by the carrier.
A real useful web service for all the designer who want to know what colors have been used on a certain image. You can even download a Photoshop Swatch file containing the color palette of the image.
