Spyware is a significant problem for most computer users. The term “spyware” loosely describes a new class of computer software. This type of software may track user activities online and offline, provide targeted advertising and/or engage in other types of activities that users describe as invasive or undesirable. While the magnitude of the spyware problem is well documented, recent studies have had only limited success in explaining the broad range of user behaviors that contribute to the proliferation of spyware. As opposed to viruses and other malicious code, users themselves often have a choice whether they want to install these programs. In this paper, we discuss an ecological study of users installing five real world applications. In particular, we seek to understand the influence of the form and content of notices (e.g., EULAs) on user’s installation decisions. Our study indicates that while notice is important, notice alone may not be enough to affect users’ decisions...