Generating a privacy footprint on the internet

As a follow up to characterizing traffic deemed as unwanted by Web clients such as advertisements, we examine how information related to individual users is aggregated as a result of browsing seemingly unrelated Web sites. We examine the privacy diffusion on the Internet, hidden transactions, and the potential for a few sites to be able to construct a profile of individual users. We define and generate a privacy footprint allowing us to assess and compare the diffusion of privacy information across a wide variety of sites. We examine the effectiveness of existing and new techniques to reduce this diffusion. Our results show that the size of the privacy footprint is a legitimate cause for concern across the sets of sites that we study.