The infographic below provides good, entertaining definitions of the terms white hat, grey hat and black hat hackers courtesy of Exigent Networks. As the infographic explains, there are some, well, grey areas between categories—for example, there is sometimes a fine line between grey hats and black hats.
Some might also disagree with the choices of white hat hacker examples. The telecom industry, for example, might consider Steve Wozniak’s early hacking exploits theft of services rather than hacking for the greater good. And Julian Assange’s qualifications will be tinted by whatever political lens through which an individual judges his actions.