Dunbar’s Number is the maximum size of a social group before it becomes impossible to have proper meaningful social interaction.  From Less Wrong:

Another problem with our oversized world is the illusion of increased competition.  There’s that famous survey which showed that Harvard students would rather make $50,000 if their peers were making $25,000 than make $100,000 if their peers were receiving $200,000—and worse, they weren’t necessarily wrong about what would make them happy.  With a fixed income, you’re unhappier at the low end of a high-class neighborhood than the high end of a middle-class neighborhood.

But in a “neighborhood” the size of Earth—well, you’re actually quite unlikely to run into either Bill Gates or Angelina Jolie on any given day.  But the media relentlessly bombards you with stories about the interesting people who are much richer than you or much more attractive, as if they actually constituted a large fraction of the world.

So what if we lived in a world where adverts and TV programming was designed for us, specifically to make us feel better about ourselves?  Everyone is happy, because everyone thinks that they live at the high end of the neighbourhood.

Do you think that kind of world is possible?  How would you go about segregating people into groups of less than 150, given the number of people in the world today?