Malware
Adware is a type of malware that earns the program authors money with advertising. These programs show users ads and force them to use websites that make money for the malware writers. Adware will also find personal information about the victim (such as their age, race, and job). This is so the malware authors can sell the information to other people. A user can usually uninstall adware easier than most malware. However, this is still difficult to do without a specially-designed program.