Like hackers, crackers sometimes break into other networked computers and either commit crimes from that computer or crack that computer's codes. Cracking is more subversive than hacking but is not always illegal. Script kiddies do not write their own codes, but merely launch someone else's the same way a consumer launches Windows or other software. They are often scorned by more knowledgeable computer whizzes. A common cracker prank.
Defacements are personal Web pages crackers post over pre-existing Web sites they have cracked.
Computer code that can fill in the security gaps crackers use to break into Web sites. Though we've heard about them for more than a decade, hackers are a whole new animal. If I had a girlfriend things would be different. Hacking and defacing will always remain something only for da underground. If the Internet was New York, then the hacking scene would be some ghetto like Brooklyn or something.