What is PhotoDNA ?

  The new technology called Photo DNA was developed by Microsoft and Dartmouth College and converts known images of child pornography into a mathematical pattern that will reveal each photograph’s unique signature. This signature can thus identify the photo despite various modifications done to it, and can track it to every online location it moves to after its original posting.

How does it work ? 

  PhotoDNA developed in collaboration with Microsoft Research and Dartmouth, in order to find digital copies of the same image to an image similar to fingerprints, signatures and images that make up a unique signature with a comparable image matching technology.

Who is already using PhotoDNA?

  Also Facebook to using this technology it is important for child abuse.

What does Google do about this problem of unwanted photographs on the internet?

  Child sexual abuse images on Google has a zero-tolerance policy. On child sexual abuse images prohibit all forms of advertisements. Host your sites search engine results, or child pornography, child sexual abuse images or event notice and the appropriate authorities will let you know when we will remove them. Child sexual abuse images are used to publish any Google accounts will be closed immediately.

In my opinion is it a good idea?

  Of course it is in this kind of  topics these things always should be..