From what I know, it means all the generations which have grown up during the wall time, for example my parents, which were born when the wall already existed and lived with the wall for quite 30 years. Instead of my generation, their generation has learned to be very patient. For example, if you wanted to have a car, you needed to wait 15 years for it and you were not able to make vacation in western european places. And when you went to buy food in the supermarket, you always went in with the question "What do they have today?" instead of todays question "What do we want to eat today?". These are problems, which the generations today have never learned about. They cannot imagine that just 25 years ago, you went into the supermarket and you couldn't find anything like today. My father told me, if you were able to find ketchup in the supermarket, you bought more than you needed, because you never knew when it will be on stock again. Today you can be sure that you will always find ketchup in the supermarket. This is something, todays generation cannot understand anymore, because they were born and grew up after the wall. Only the wall generation knows and remembers.

@Florence: Your welcome. :) Wand is more used for the wall inside your home, which keeps your house together, while Mauer is mostly used for defense constructions. You might experience very often, that one german word can have different meanings. I do not know if germans carry the family name Mauer but you will find germans with the family name "Maurer" which comes from the job of the guys which build a Mauer. :) The Maurer is building the Mauer. :)

It is referred to the people living in East Germany (DDR).

I would like to add, that "Generation Mauer" is a word creation, usually used in an academical or literary way. My generation for example is called "Generation Praktikum" in articles, newspapers, etc. "Praktikum" means "internship", and we are called after this, because we are all doing internships :-D

Vielen Dank für die Informationen!