Adware is software that displays advertising banners on Web browsers such as Internet Explorer and Mozilla. While not categorized as malware, many users consider adware invasive. Adware programs often create unwanted effects on a system, such as annoying popup ads and, in some instances, the degradation in either network connection or system performance.
Adware programs are typically installed as separate programs that are bundled with certain free software. Many users inadvertently agree to installing adware by accepting the End User License Agreement (EULA) on the free software.
Adware are also often installed in tandem with spyware programs. Both programs feed off of each other's functionalities - spyware programs profile users' Internet behavior, while adware programs display targeted ads that correspond to the gathered user profiles.