[pgroves]

Facebook now acknowledges what we said for a long time and they didnt acknowledge, that every single photograph uploaded to Facebook is put through facial recognition software they call PhotoDNA which is used to find people for whom any law enforcement agency in the world is looking.

How true is this?

[pbburrell]

I don't think it's very true at all. From what I've read, PhotoDNA is used to detect child pornography by comparing a photograph's "hash" against a database of hashes for known pornographic images. There's no facial recognition involved.

More here:

http://news.ycombinator.com/item?id=2564235