Adware - is a program which shows advertisement on your computer mainly through pop-up windows and banners. Adware programs are often installed in exchange for another service, such as the license to use a software without paying for it. In order to use free software's many users allow the installation of adware on their computer.

But most of the time the adware can be very annoying, as Adware continuously displays ads through pop-up windows and banners. To display ads the adware connects to its server and will regularly download and upload data. Thus adware takes much of your Internet bandwidth and will cause slow download speed. Adware will also use your computer system resources such as computer memory and this ends up in slow computer performance and even cause computer crash. Some adware programs pop-ups ads in such a way that you will not be able to visit websites or do normal work on your computer.       

Nowadays adware is designed with the functionality of spyware. Spyware is often associated with software that displays advertisements (called adware) or software that tracks personal or sensitive information. Adware collect user's Internet browsing information and transmit it to the remote server, so that adware can display more relevant ads. Zango, Kazza, CometCursor, Gator and Bonzi Buddy are few most common adware bundled free programs found on Internet. Adware is considered as a security risk by most of the virus protection software's.