Real organized criminals don't use indexed websites.
Youtube's major legal problem is piracy - not a threat buried within a 2 hour livestream.
More creditable threats are subtle not dead or alive playing in the background with an overturned car and someone having a Mel Gibson meltdown.
As I recall Jared Loughner had a edge lordy video of him busting up boom boxes to gain respect.
As much as places like 4ch been perceived in the old media as the
DARK INTERNET 
it isn't.
Twitter is filled with twits and broken AIs - Remember when Sam Biddle thought some ISIS videos were funny?
Or the time Gawker tricked a Coca-Cola bot into making Mein Kampf ASCII art?
These people are ultimately hypocrites.
In the end the internet only provides information not reality,
Or for certain individuals who took media literacy at Bard College,
But probably just watched movies:
Techne not
Episteme.