The main "social character" of our society, according to Fromm, is the "alienated man."
In this essay, Fromm argues that each type of society produces the "social character" that is needed in order for that society to function. Our modern society is (or at least the society of Fromm's day was) an industrial society. It is also, quite importantly, a bureaucratized society. Because of this, it needs a social character who feels free and independent, but who is actually completely willing to conform to the needs of the organization where he or she works. Those people also need to consume material goods constantly as a way to fit in with their society outside of the work setting.
Fromm argues that such people are alienated from themselves. They are no longer able to act on their own. Instead, they are completely controlled by the forces of the society in which they live.