Bloodshed in the US made for some terribly sad headlines last week. A streaming video on Facebook showed a police officer fatally shoot a black man in Minnesota, sparking national outrage and claims of racial injustice, followed a day later by the killing of five police officers in Dallas by a lone sniper who vowed revenge on white people.

Philando Castile's death also was preceded on July 5 by the fatal shooting of another black man, Alton Sterling, by police in Baton Rouge, Louisiana.

"Too many shootings and hatred on the media, no matter if they are traditional or new media," complained a friend of mine. "I'm so fed up with the information bombarding nowadays."

As a journalist who was taught on the first days about gatekeeping and agenda-setting theories, and about media ethics and professionalism, I can't help but wonder what has gone wrong with media today.

In the digital era when anyone can claim to be a "journalist", who should be in charge of news selection and decide what should be told to the public?

First instituted by German-American social psychologist Kurt Lewin in 1943, the gatekeeping theory has provided a solid foundation for traditional media practice and editorial operations worldwide.

Irrespective of social systems and ideology, gatekeeping requires a media practitioner to abide by social and human ethics and safeguard the public's right to know the "right things".

According to scholars Pamela Shoemaker and Tim Vos in the field, gatekeeping is the "process of culling and crafting countless bits of information into the limited number of messages that reach people every day, and it is the center of the media's role in modern public life. This process determines not only which information is selected, but also what the content and nature of the messages, such as news, will be."

At traditional media outlets, reporters usually decide which sources are included in a story, and editors decide what gets published.

Technology and innovation make instant communication a click of a mouse away. Although individuals are expected to act as gatekeepers by filtering information before disseminating it through an e-mail, blog or video, is it asking too much for each social media user to play a more responsible role in producing and distributing content through sites such as Twitter and Facebook?

Consider the video that captured the last moments of the life of Philando Castile, 32, who died when he was shot by an officer in his car on July 6 in Falcon Heights, Minnesota.

When stopped by a police officer for a registration check, Castile told the officer in his car that he had a pistol that he was licensed to carry, and instead of sitting quietly without moving, he "tried to get his wallet out". The officer then shot him numerous times.

In the five-minute video, a woman sitting next to Castile filmed the last minutes of his life. Blood soaked through his shirt, and he seemed to be suffocating.

The policeman, shaking and sobbing in the background, can be heard saying, "I told him not to reach for it. I told him to get his hand out."

The video has caused a widespread reaction, from the president down to the streets in many cities of the US and around the world. However, the damage can be stemmed if society can reach a consensus and move toward establishing a gatekeeping system.

We can't rely on Facebook for information-filtering. We can't expect Mark Zuckerberg to acquire journalism credentials. However, each of us can at least decide what we want to post and to whom we want the information to reach.

Contact the writer at junechang@chinadailyusa.com