Both incidents in the United States had to do with African American Rights a and "Wrongful" deaths by police officers. They are different in one was much more justified than the other. In the first case the public misinterpreted the story and the riots and the protests got out of hand. Whereas the other incident had a video that was given to the press that gives Americans a concrete way to make opinions on the matter.
Many major protests in history happened without social media, mostly because the issues were so important that everyone wanted to be a part of them, but it wonder if some of these outrages would have happened without social media, and I think they would.