It's a standard term familiar to anyone who knows anything about challenges faced by segments of society other than their own.

If you don't know what you're talking about, don't care to look it up, and didn't pick up the examples already given in the thread including the context you pulled it from, then maybe you don't have a lot to say?

Incidentally, they are a major consumer group; in fact there are whole, rather exploitative industries, for which they are nearly the entire customer base. So in fact yes, people do organize business around that.