Distributed Denial of Service attachs have been used to rob banks, disrupt media sites belonging to Al Qaida, Fox. At the time of writing China and Eastern Europe were sources of the biggest DDoS attacks on Australia. Some hacking is by Chinese millitary and some hacking by retired Chinese virtual cyberwarefare experts turn their attention to criminal activities such as extortion, threatening to shut down online businesses if they don't pay.
Chinese Peoples Liberation Army's millitary industrial espionange Unit 61398 enguage in cyber attacks against the West. They enguage in intelligent collection to provide Chinese businesses with stolen interlectual property. When you click Australia the DDoS map above it shows there is more DDoS out of Australia to China than the other way so I guess there is some propaganda associated with the ABC video documantary / report "Hacked" below.
Some cyber criminals hack secure computer systems not for immediate gain but for notoriety. When they're released from prison they're are headhunted by security firms to work for them.