what is cyber theft ?

Computer crime or cybercrime refers to any crime that involves a computer and a network, where the computers may or may not have played an instrumental part in the commission of the crime (Moore 2000). Issues surrounding this type of crime have become high-profile, particularly those surrounding hacking, copyright infringement, child porn, and child grooming. There are also problems of privacy when confidential information is lost or intercepted, lawfully or otherwise.
On the global level, both governments and non-state actors continue to grow in importance, with the ability to engage in such activities as espionage, financial theft, and other cross-border crimes sometimes referred to as cyber warfare. The international legal system is attempting to hold actors accountable for their actions, with the International Criminal Court among the few addressing this threat.

cyber thefts nowadays are becoming a big concern .computer viruses are designed to steal the personal information such as bank account numbers, credit cards data.worms and Trojan horses are attaching many computer programs.social networking sites, like Facebook, are among the most commonly targeted because of their huge communities of users .
In my opinion ,these uncertanties and unsecured sites makes people reluctant of using internet and computers as a means of purchasing goods and services.
Experts say Internet users can keep safe by being circumspect about sharing personal information, and making sure their computers have up-to-date anti-virus programs. but can it be really like that? as I see that, even using up-to-date anti-virus programs don't makes us secured . I myself had face a lot of problems even though I use anti-viruses.
What is your opinion?