Adware is software that displays advertisements automatically on a computer. It is often downloaded accidentally with freeware or through an email. Antivirus programs can scan a computer for adware and remove it.
Adware can interfere with other software or disrupt the functionality of the operating system. Pop-up ads and an additional browser toolbar are both signs that adware has been installed. Removing adware can be complicated and may violate the terms of the End User Licensing Agreement for the free software it accompanies. Adware that tracks Internet usage and collects data on the types of websites visited and the amount of time spent on the websites is called spyware.