What really happens when you hit Like?

Have you ever got a picture that promised to do something amazing if you just press Like? Have you been asked to press Like that in turn will donate a dollar to sick children? A promise of new iPhone as a gift for your Like? It’s probably a fraud.

Here is the classic example of this type of fraud - the attacker raises up an image, typically one that creates an optical illusion. The picture is attached with the following text: "The picture that leaves you surprised! Step 1: Click on the image. Step 2: Hit Like. Step 3: Type ‘1’ in the response field and watch an amazing result!". Under the picture you will see some names of your friends that also “Liked” it, so apparently it seems to be legit, and because you also want to be ‘surprised’ you press Like, add the ‘1’ response and ... nothing happens. Or so it seems.
The fact that you followed the instructions was actually distributing the image and the page in which it appears to all your friends, so that they in turn see the image, follow its instructions and... nothing happens for them as well.