This will just explain the differences between the kinds of people who live in the hackerworld.

Script kiddies: These are the lamest people in the hackerworld, in fact they are not part of it because both white and black hats hate them. They are mostly unable to program, they just run other people's programs without knowing how it works. The only thing they do is mail bombing, defacing random websites,...

black hats: a.k.a crackers, these are the "evil" crackers, the difference between script kiddies and crackers is that script kiddies attack random systems because they are to lame/dumb/...
to be able to exploit a somewhat harder system. Crackers pick a system and keep trying to exploit it.

white hats: consider them the "real" hackers. The internet and *nix wouldn't exist without the white hats. These people do not crack computers but secure them. Ofcourse these hackers are able to exploit computers but they just don't do it. Another problem is that the media calls the black hats/script kiddies hackers wich irritates real hackers in no end.

gray hats: These are neutral people, they just publish information and you deside what to do with it, either use it to crack or to secure.