A research team bought over a hundred used hard drives for about a thousand dollars, and found more than half still contained personal and commercially sensitive information — some of it blackmail material.
People have repeated this experiment again and again, in a variety of countries, and the results have been pretty much the same. People don’t understand the risks of throwing away hard drives containing sensitive information.
What struck me about this story was the wide range of dirt they were able to dig up: insurance company records, a school’s file on its children, evidence of an affair, and so on. And although it cost them a grand to get this, they still had a grand’s worth of salable computer hardware at the end of their experiment.