prole.info on class and the meaning of "proletarian".
"Prole" is short for "proletarian" a word used by Karl Marx to describe the working class under capitalism. We are all the people in this society who do not own property or a business we can make money from, and therefore have to sell our time and energy to a boss--we are forced to work. Our work is the basis of this society.
We are not just a sociological category. Work, and the society that grows out of it are alienating and miserable for us. We are constantly fighting against the conditions of our lives. Simply standing up for our own interests brings us into conflict with bosses, bureaucrats, landlords, police and politicians everywhere. These everyday struggles are the starting point to undermining capitalism. We are not just the working class; we are the working class that struggles to do away with work and class, and the society built around them.
The experience of those who are forced to work, and who struggle against the society based on work, creates certain kinds of ideas. When we are actively fighting for our own interests, these ideas solidify into a subversive, anti-capitalist perspective. This has at times been called "communism" or "anarchism". We do not need political groups to bring us these ideas, but we do need to think about how to fight for ourselves.