So, the question is how much time do we really spend on the internet. You go in just wanting to check something, only to find yourself logging off hours later and in a state of awe in how much time was wasted without even knowing. That is the "hijacked brain" of internet addiction. Social media, chat forums, blogs, websites, videos, how-to's, music, games, shopping, e-commerce, celebrity gossip etc. all include time spent on the web.
The "hijacked brain" that is referred to is a metaphor for what we experience when we become lost in time, but our brains are well rewarded with the lighting up of the brain pleasure center and releasing feel good chemicals. These feel good chemicals dopamine and adrenaline are chemicals that get you high within your own body, as referenced in the video as that of a compulsive gambler. Risk taking and winning will increase adrenaline, which it is known, our own body creates, and becomes addicted to, ie: "adrenaline junkie."
In social media sites, you can post something. Then you wait for a response. You get a response and that is a rush. More social acceptance, so you engage more and the cycle continues just like the gambler at the blackjack table. More and more, like it is never enough. Next time you go out, take a look around. Here in Florida people are at restaurants, bus stations, airports, and any other public venue. Most people are plugged into their smartphone, or some other form of electronic device.