Another kind of danger is one of national security. All sorts of vital functions of the nation are dependent on the internet. In past years, there has been evidence of the Chinese (among others) launching attacks on various countries' vital functions.
For example, the US banking system is almost completely computerized. A concentrated attack that shut down the banking system could easily disrupt the US economy, costing the country billions of dollars in lost productivity. For this sort of reason, national security experts are gravely concerned about attacks from hackers and viruses.
In the electronic age that we are in most of our personal data and that of businesses is stored in an electronic form instead of on paper. Information that should not be seen by others is being constantly transferred over the internet and available for others to steal when offline too.
Hackers are always eager to break into the databases of businesses like banks to obtain passwords using which they can transfer funds into their own accounts. Confidential information of businesses in the hands of hackers can be sold to competitors or used to make profits on the stock market in what is called insider-trading.
Hackers try to access personal information of individuals using software like viruses and spyware. Some do not have an intention to gain access to information but instead create viruses to corrupt data, make programs unusable and generally cause inconvenience to others.
It is therefore essential for businesses and individuals to have reliable firewalls to protect themselves, closely monitor computer activity, install software from reliable sources and always stay alert.