Over the past decade, advertising has emerged as the primary source of revenue for many web sites and apps. In this paper we report a first-of-its-kind study that seeks to broadly understand the features, mechanisms and dynamics of display advertising on the web - i.e., the Adscape. Our study takes the perspective of users who are the targets of display ads shown on web sites. We develop a scalable crawling capability that enables us to gather the details of display ads including creatives and landing pages. Our crawling strategy is focused on maximizing the number of unique ads harvested. Of critical importance to our study is the recognition that a user's profile (i.e., browser profile and cookies) can have a significant impact on which ads are shown. We deploy our crawler over a variety of websites and profiles and this yields over 175K distinct display ads. We find that while targeting is widely used, there remain many instances in which delivered ads do not depend on user profile; further, ads vary more over user profiles than over websites. We also assess the population of advertisers seen and identify over 3.7K distinct entities from a variety of business segments. Finally, we find that when targeting is used, the specific types of ads delivered generally correspond with the details of user profiles, and also on users' patterns of visit.

Understanding the empirical characteristics of broadband performance is of intrinsic importance to users and providers, and has been a significant focus of recent efforts by the Federal Communications Commission (FCC)[9]. A series of recent studies have reported results of empirical studies of broadband performance (e.g.,[11,15,22]). In this paper, we reappraise previous empirical findings on broadband performance. Our study is based on a unique corpus of crowd-sourced data consisting of over 54 million individual tests collected from 59 metropolitan markets over a 6 month period by Speedtest.net. Following analytic approaches from prior studies, our results confirm many of the raw performance results (upload/download/latency) for ISPs in specific US markets. However, the size and scope of our data enable us to examine the details of characteristics that were not identified in prior studies, thereby providing a more comprehensive view of broadband performance. Furthermore, we also report results of broadband performance characteristics in 35 metropolitan markets outside of the US. This not only provides an important baseline for future study in those markets, but also enables relative comparison of broadband performance between markets world wide.