The advent of information technology has enabled firms to collect significant amounts of data about individuals and mine the data for developing their strategies. Profiling of individuals is one common use of data collected about them. It refers to using known or inferred information to categorize the type of an individual and to tailor specific strategies for that individual. Proponents of profiling claim that profiling enables firms to target their limited resources more effectively and efficiently, which benefits society by reducing various deadweight losses. However, profiling opponents, including some of those consumers and users who are profiled, point out concerns related to privacy, discrimination, and effectiveness. In this dissertation, I theoretically and empirically study the impact of profiling and profiling policies on the firm that employs profiling, the consumers or users that are profiled, and society. Specifically, the first and second essays study profiling in the context of online marketplaces and the third essay investigates profiling in the context of security. As a compromise between a ban and an unfettered use of profiling, the U.S. government favors a voluntary profiling approach in online marketplaces. Implicit in this policy is the supposition that since consumers can choose to be profiled or not, no consumer will be worse off. In the first essay, however, I show that every consumer that chooses not to be profiled, and more importantly, some consumers that choose to be profiled, are worse off compared to when there is no profiling. Furthermore, neither social welfare nor the total consumer surplus is necessarily higher under the voluntary profiling policy than under the no profiling policy. In the second essay, I empirically show that those consumers who have higher privacy concerns and low search costs are likely to disclose their information. In addition, the firm does not always reward those consumers who disclose their information. The proponents of airline passenger profiling claim that profiling will improve the performance measures of security systems in various dimensions. In the third essay, however, I show that if Transportation Security Administration (TSA) structures the security systems as it did when it deployed Computer Assisted Passenger Prescreening Systems (CAPPS), then using profiling is superior to no profiling on those performance measures if and only if the quality of the profiler vis-a-vis that of the screening system is sufficiently high. If TSA deploys two screening devices along with the profiler, on the other hand, profiling improves the reliability of screening device signals, reduces the inconvenience caused to normal passengers, and improves social welfare even when the quality of the screening device is high. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]