Can I consider television, music, and video games the most important aspects of popular culture?
Television, music, and video games are significant forms of popular culture, but the internet might even be more significant because of social media and the ways people can interact on the internet.
Popular culture is what ordinary people care about and is influenced, if not created, by mass media. Social media is definitely a part of mass media, since social media is based on an intersection between corporate media producers (e.g., Facebook corporation and Google corporation) and ordinary people. In fact, the internet media is so powerful that we have a name for ideas that enter popular culture through this means: "viral memes." Look at the "ice bucket challenge" and see how this meme ran through social media for awhile; people influenced others' behavior by challenging their friends to dump ice water on their heads.
It is likely that social media is more powerful than television and music because social media websites invite active participation from users. Even video games often have a social media element to them when it comes to playing them online. This could be very powerful for youngsters in juvenile detention, since first-person shooting games give young men, in particular, a sense of power.
When working with young people, it is critical to know and understand the social media they are using, including those associated with video games. A few years ago, Facebook was really popular with college-aged students. Now, this age group may be more likely to use Twitter, Snapchat, or Instagram.
Research is only as powerful as it is able to represent the realities of the research subjects. Today's youth are involved in a much larger range of popular media than youth were even ten years ago, and this involvement evolves quickly.