http://www.businessinsider.com/google-warns-we-are-scanning-your-email-2014-4 [businessinsider.com]

Yes, they've always said that they have an algo that "reads" emails and determines what kind of ads to display.

This guy had pics attached to an email. Sooo, either the algo is so good that it can determine that these pics were p*rn OR, someone at google opened this email, and the attachments, to make that determination.

Sooo, either the algo is so good that it can determine that these pics were p*rn OR, someone at google opened this email, and the attachments, to make that determination.

from the article linked in your OP...

http://finance.yahoo.com/news/google-spotted-explicit-images-child-160034446.html [finance.yahoo.com]:

Since 2008, we’ve used 'hashing' technology to tag known child sexual abuse images, allowing us to identify duplicate images which may exist elsewhere. ...

That's pretty cool, not sure how I missed that.