TV changes everyone it touches.
TV brings mass. For fifty years, TV meant that programmers and advertisers had a very good chance to reach everyone, or almost everyone, at the same time. TV integrates a culture, because there's instant common touchstones being generated daily. (When I say, "yadda yadda yadda" or "where's the beef," you know what I mean, right?)
TV brings pluralism and diversity. This seems to contradict the first, but it doesn't. Once TV has opened a channel to the brain, it can bring in whatever it chooses, without clearing it with you first. So, the viewer can discover that people-who-don't-look-like-us aren't so different, or that women might be good cops, or that a member of the [insert oppressed group] might also be a person too.
and finally, TV brings dissatisfaction. Advertising needs to make you dissatisfied to work. And picture perfect sitcom families have more money and less trouble than most folks (because they're not real).
Now, of course, TV isn't what it used to be. No more three-channel universe. That means that the cable/internet virus changes everyone in a very different way. Call it the million channel world (mcw).
The mcw brings addressability. There is no mass any more. You can't reach everyone. Mad Men is a hit and yet it has only been seen by 2% of the people in the USA.
The mcw bring silos, angry tribes and insularity. Fox News makes a fortune by pitting people against one another. Talkingpointsmemo is custom tailored for people who are sure that the other side is wrong. You can spend your entire day consuming media and never encounter a thought you don't agree with, don't like or don't want to see.
And finally, I have no idea if the mcw is making us happy. Surely, a substantial use is time wasting social network polishing, and that's not really building anyone's long-term happiness. And the mcw makes it easier to get angry, to waste time (there's never 'nothing on') or become isolated. Without a doubt, the short-term impact of mcw is that it makes it easy to spread terror and harder to settle on the truth. At the same time, there's no doubt that more people are connected to more people, belong to more tribes, have more friends, and engage more often than they did before it got here. We got rid of some gatekeepers, but there's a race for some new ones. In the meantime, a lot of smart people are fending for themselves, which isn't so bad.
One thing we learned from the TV age that's still true: more media is not always better, particularly when we abdicate our power to filter and choose.