In the Syrian context, that often turned political. Supporters and opponents of the Syrian government have waged digital wars reporting each other's channels or videos, prompting YouTube to close some. Many videos were lost, including footage of a 2013 chemical attack in a Damascus suburb.
Under pressure in Europe and the West to do more to rein in extremist content, YouTube introduced a number of new measures, including machine learning, which trains itself to recognize patterns in enormous numbers of videos. It identifies "objectionable" material, which is then reviewed by human experts to determine if it should be taken down.
A YouTube spokesperson said the machine learning can remove "a lot of content at a scale."
"The vast majority of time our reviewers get it right. And when we make mistakes, we act quickly to correct them," the spokesperson said, speaking on condition of anonymity in line with company regulations.
The spokesperson said activists need to improve their data when uploading videos, properly identify them as documenting rights violations and provide context. Meanwhile, the machine learning is being tweaked.
Robin Gross, the executive director of the San Francisco-based IP Justice, an organization that promotes internet freedom, said powerful images, even if bloody, can change the minds of the public, as they did in the U.S. war in Vietnam.
"Machine learning software doesn't evaluate the importance of understanding conflict and how an image, even a graphic one, can contribute to better understanding of a situation, which is necessary for addressing it," Gross said in an email.
The closures' suddenness and breadth stunned those documenting the conflict. Many opposition activists already feel the international scene is turning against them as the Syrian government and its allies make major battlefield gains. Some were convinced the YouTube shutdowns were because of political pressure.
"There are attempts to finish off the conflict in Syria by any means, including having no coverage or a total blackout on the media by the Syrian opposition," said Tala Kharrat, English department manager for Qasioun News Agency, whose channel was among those shut down and subsequently reopened on appeal.
Another prominent news platform, the Shaam News Network, has nearly 400,000 videos on its YouTube channel, viewed some 90 million times. In July, its operators found a message saying their channel no longer exists.
Mizyan Altawil, spokesman for SNN, said his network is no stranger to scrutiny of its content, but this time the shutdown was different, with no prior warning. Even more confusing, the channel was reinstated, only to be closed again, then reopened. "We are constantly on the alert," Altawil said.
The Syrian Archive reached out to activists and media groups affected by the removal and contacted YouTube to restore them. With a team of six and a budget of $96,000, the Archive is also downloading videos to its own server, an expensive and labor-intensive endeavor. The group is partially funded by Google through its Digital News Initiative.
Al-Khatib said the group knew the issue will come up one day, given concerns over proliferation of violent content, and that it was always a "grey area" how long YouTube would handle graphic material.
But the best evidence for war crimes can come from videos showing violence, even ones uploaded by the perpetrators with the intent to terrorize, like an execution video. Sometimes such videos identify and show the faces of militants.
"If they take it down, there will be no graphic content but there will be no evidence."