We live in a globalized world. This means that technology is rapidly spreading across the world, that goods and services are cheaply available to most people, and that humans are more connected than ever before.
Unfortunately, it also means that a lot of people are being exploited and mistreated to produce goods and services that the general public consumes. In many cases companies operate sweatshops where employees are underpaid, overworked, and exposed to unsafe work environments. In extreme examples - such as the Chocolate Industry - conditions for workers are so bad that the work conditions are considered by many to be outright slavery. Obviously the owners of these sweatshops are committing a mortal sin (specifically the mortal sin of defrauding laborers of their wages).
But, what about those who buy products produced using exploitation? Is it a sin to eat chocolate or purchase electronical products even knowing that they are manufactured using unfair practices? If so, how severe a sin is it?