Everyone knows Prometheus stole fire from the gods on behalf of mankind. That’s all some people, especially youths, today need know to inspire them to adapt Prometheus as their icon, and to adapt the Greek deity’s name for their online monikers.
The actual Greek myth is a bit more complex. In a reductionist nutshell: Prometheus is a Greek god of Olympus, ruled by Zeus. He initiates animal sacrifices. One day during a sacrifice he sasses Zeus. He cuts up a bull and divides it into two parts: one containing the flesh and intestines wrapped up in the skin; and the other consisting of only bones and fat. Prometheus asks Zeus to choose his share; the rest is to be given to man. Zeus picks the bones and fat, making him bitter against Prometheus and against humankind. Zeus punishes the mortals by withholding from them the gift of fire. Prometheus steals it back. Then Prometheus—who is known to have the gift of foresight—further sasses the great god Zeus by predicting that one of Zeus’ children would one day dethrone him, but refusing to say which one. The enraged Zeus punishes Prometheus by binding him in steel chains to a rock in the Caucasus Mountains. There, every day for eternity, an eagle is sent to tear and eat Prometheus’ liver. Every night, the god Prometheus’ immortal liver renews itself so that he can be tortured again in the next day’s light.
Sources: Counterculture Through the Ages by Ken Goffman & Dan Joy