If you spend a lot of time on internet you no doubt have heard of Bernie Sanders. If you only watch TV you might not think of him as a viable candidate or you might not know who he is at all. Sanders is a victim of media blackout. This also explains why he has so much support from young people and why it has taken him so much more time to reach poorer minority groups and seniors.
Leading up to the 2nd gulf war, there was a media blackout on the information about the WMDs that Iraq supposedly had. If you were an expat of the US at this time you probably looked on in horror as your homeland walked senselessly into a war based on lies. Many Americans still believe that Iraq did have WMDs, but that is a different story.
The huge protests going on in the US and France are not getting much media coverage nor is the 36,000 strike of Verizon workers. When it is covered it is covered from the angle of how it will inconvenience customers.
When media blacks out these kinds of stories it is complicit in the results. How long did it take for the child abuse in the catholic church to come to light and even if you had heard of some cases did you know it was 1 in 10 priests?
During WWII the government asked the media not to cover the Japanese fire balloon attacks on American soil so that the Japanese would not know the effectiveness of the weapons. Did you know about that?

Japanese fire balloon