A live, 10-minute video of the aftermath of a police officer shooting a black man in Minnesota was the latest example of the riveting power of video streaming and the complex ethical and policy issues it raises for Facebook Live and similar features.
The graphic video taken by the victim's girlfriend and broadcast on her Facebook page shows Philando Castile covered in blood in the driver's seat of a car as the officer points a gun into the vehicle.
By Thursday morning, the footage had more than four million views and together with another police shooting in Baton Rouge, Louisiana, topped the items on Facebook's "Newswire", which promotes stories of broad interest.
Facebook this year has made its Live feature, which allows anyone to broadcast a video directly from their smartphone, a central component of its growth strategy. Rivals Twitter and Alphabet's YouTube are also pushing live video as a new frontier in Internet content.
While traditional TV broadcasters are subject to "decency" standards overseen by the Federal Communications Commission - and have a short delay in their broadcasts to allow them to cut away from violent or obscene images - Internet streaming services have no such limitations.
That easy accessibility and openness are fostering a new type of intimate, personal broadcasting that proponents said can be extraordinarily powerful, as evidenced by the demonstrations that began shortly after the Minneapolis video.
But critics said the lack of regulation can allow a somewhat cynical exploitation of tragedy.
Facebook and others can "rush forward and do whatever they think will get them clicks and users" without concerns for potential legal consequences, said Mary Anne Franks, a law professor at the University of Miami who helps run the Cyber Civil Rights Initiative. She advocates on behalf of revenge porn victims and would like companies to do more to prevent dissemination of such content.
Indeed, Internet companies enjoy broad protections under federal law for content users posting on their services. Merely hosting third-party content that is objectionable or even illegal does not expose those companies to litigation as long as they adopt reasonable takedown policies.
The companies do enforce their own terms of service, which restrict many types of images. They rely heavily on users to report violations, which are then reviewed by employees or contractors for possible removal.