Adware is software with advertising functions integrated into or bundled with a program. It is usually seen by the programmer as a way to recover programming development costs, and in some cases it may allow the program to be provided to the user free of charge or at a reduced price. The advertising income may allow or motivate the programmer to continue to write, maintain and upgrade the software product.
Some adware is also shareware, and so the word may be used as term of distinction to differentiate between types of shareware software. What differentiates adware from other shareware is that it is primarily advertising-supported. Users may also be given the option to pay for a “registered” or “licensed” copy to do away with the advertisements.
Spyware is computer software that is installed surreptitiously on a personal computer to intercept or take partial control over the user’s interaction with the computer, without the user’s informed consent.