Hacker, cracker.. The distinction is no more in popular culture. In anycase, the reason people get hacked is simply b/c they don't "know" about computer security.
Not stupid mind you. A person could be perfectly smart without knowing anything about computers. And a lot of "dumb" people claim to know computers simply b/c they can do some retarded thing with/on it.
Hackers/crackers are successful simply b/c people venture into the unknown. If you don't understand things inside out, you should probably not use it with your financial accounts. Even simple online banking. How many people actually verify the certifates when they go to a site. Or worse yet.. That little pop up window you get asking you to "authorize" a certificate?.. My God. I wonder how many people actually click "yes" to that.
Anyways. Education is the most important thing. These greatest and latest firewalls and stuff are just bullshit. A smart user is better than them all.