Hackers' motivations vary. For some, it's economic. They earn a living through cyber crime. Some have a political or social agendatheir aim is to vandalize high-profile computers to make a statement. Others do it for the sheer thrill.
When asked by the website SafeMode.org why he defaces web servers, a cracker replied, "A high-profile deface gives me an adrenalin shot and then after a while I need another shot, that's why I can't stop."