While revenge porn and stuff is bad, there are a number of known child related incidents.
So if a private group of scumbags, are posting stuff to a private group, noone will know unless someone within reports.
Who needs the darkweb when u can have a private Facebook group?
Edit: as per replies below, they do use image recognition aswell for I guess known content lists
Here's an example: if you go on YouTube you can find harmless videos of parents bathing their babies, and I doubt anyone would call that child pornography. Same goes for something like a birth video, even though it shows a vagina. How do you detect the differences?
I think it'd be an improvement if Facebook were more open with their policies and allowed nudity, even if it required flagging content as mature. To get around this people end up placing tiny black bars in any of the "offensive" parts. But how does that seriously change anything?
I'd say it's pretty reasonable to request users flag content. Detecting it programmatically is currently impossible, so what other choices do you have if you want to allow users to upload content? Should only multi-billion dollar companies be able to have user-uploaded content? How would you handle this issue if you were building a small media sharing site?
If you can do this (with different categories, for instance, determining what is nudity, then determining black people, to automatically classify porn with black actors automatically), it would be quite impressive. Results have nearly 5% error on CIFAR-10, which is full of clearly distinct categories - planes versus boats.
Not only impressive, but likely very profitable.
> Results have nearly 5% error on CIFAR-10
Any idea what the error rate is for human classification on CIFAR-10 images?
https://en.m.wikipedia.org/wiki/List_of_file_signatures
Also check out "libmagic"