My social sphere is very diverse in ages. My friends at school range from 18 to 24 years old, while my close friends at work range all the way into their forties. I don't encounter elders very much, but I teach young kids and still consider my college friends young. I'm content with my interactions with people this age. Not that I wouldn't want to interact with elderly people, I'm just not really ever put in that position. I think our society is segregated by age because the young get mad at the old and swear and yell, then the older citizens make rules and laws to take away the youth's freedoms. It's a never ending game of cat and mouse and we're just poking each other to make each other angry. Young people are marginalized by their school status, what grade they're in, and whether they work. Adults are marginalized by jobs and schooling and even social activities. Young adults and middle-aged adults are privileged because it's the "prime of their lives". They are seen as fresh, young, and new while elders are too old and children are too young. Instead of enjoying your youth as a child, you want to be older so you can be like the adults and that's a big part of why childhood has changed so much.
Society can promote equality through age by not doing the "poking" I was talking about. If we stop attacking one another, we'll be able to communicate more. Stop taking things away from one another and we'll hear each other. I think the youth needs to respect adults more, but likewise adults towards the youth. If we work together I think ageism could be put to an end.