The move comes just days after YouTube cracked down on child-exploiting videos, and just as it had to pull disturbing autocomplete results. It has been promising stricter enforcement of its policies on both the content of videos and their comments.

As with YouTube's reaction to hate videos, the takedowns and policy enforcement measures are welcome, but also relatively late -- they're coming as advertisers are pulling out and the damage has already been done. The tougher enforcement should reduce the chances of a situation like this going forward, but the rash of discoveries suggests that there may need to be more proactive campaigns that catch abuse before it makes headlines.