'Cancel culture' is defined as "the practice or tendency of engaging in mass cancelling to express disapproval and exert social pressure."
Cancelling someone or something refers to boycotting and publicly shaming them in response to a perceived transgression, such as making an offensive comment about a marginalized group or excluding specific populations. Sometimes this can be a powerful means of social justice. For example, in 2016, the film community banded together to boycott the Oscars in response to the lack of diversity among award nominees. As a result, in 2021, a record number of people of colour were nominated for acting awards. In this case, calling out the Oscars brought awareness to the problem and helped jump-start the forward movement.

The practice can have positive and negative impacts depending on the idea for which it is used. Mass Cancelling someone who has done a ghastly act can be an effective way of annihilating the wrong from the society as it puts social pressure on banning or vanishing such organization, individual or even a group.

But the negative impacts are more when we speak of teenage cancel culture.
Cancelling someone or boycotting them publicly can sometimes aggravate the mental health of the person, specifically teens. As a result, teenage cancel culture has gained importance after the proliferation of social media in every corner of the world.

Since many people, primarily children, actively participate in social media apps, it affects them significantly. For example, boycotting a classmate by posting abhorring comments online and shaming them in front of many others who could see it quickly can deteriorate a child's mental well-being.
It can also lead to teen anxiety, depression, trauma and even suicidal thoughts or behaviour.