A pop-up download (sometimes called a download pop-up ) is a pop-up window that asks the user to download a program to their computer's hard drive. The window may feature a security warning, or some other type of message that is likely to lead to compliance. Often, the pop-up window has no information about the program to be downloaded, and may feature buttons for "download," "yes," or "ok" -- but none for "no" or "cancel." Faced with a pop-up download window, the user may think that the download in question is just a browser plug-in application needed for aspects of a Web site they're visiting, or that the pop-up window was generated by their own computer.
Pop-up downloads often install programs that track online behavior and report it back to a parent company ( spyware ) and programs that use that information to generate specific pop-up advertisements ( adware ). EarthLink, a popular Internet service provider ( ISP ) recently estimated that 40 to 50 percent of their subscribers have such applications running on their computers, usually without the owner's knowledge. Subscribers contacting the ISP to report a problem are often surprised to find that these downloads are the cause.
A less scrupulous variation of automatic installation, called a drive-by download , installs a program on a computer's hard drive without even first generating a pop-up window.