PUS Categories

At the most basic level, potentially unwanted software (PUS) installs without the user’s informed knowledge or consent, monitors certain aspects of his activity, and then transmits that collected information to a third party. Most PUS does not register in Windows’ Add/Remove Programs Control Panel and is undetectable to antivirus software, making it extremely difficult for users to remove without special tools.

The three main categories of PUS are adware, spyware, and malware.

Adware

Adware tracks the user’s Internet browsing, reports the information to a central server, and then displays advertisements based on the reported information. Adware purports to be useful in that it helps advertisers target ads only to users who will be interested in the subject of the ad, and exposes users to ads with some relevance to them. Companies using adware distinguish it from spyware because typically the user agrees to the installation and use of the adware, usually in exchange for a service such as a free e-mail account or current localized news or weather information. But some adware installs without the user’s knowledge or consent, or the personal information that the software exposes to the advertiser is not clear because the details about the information collected and transmitted is buried in the legalese of End User License Agreements (EULAs) or convoluted privacy statements. Examples of adware include tracking cookies installed by advertising companies, which can be used to determine when a user has visited any Web page with an advertisement provided by that company—even if these pages appear on many different domains and Web sites.