Ads versus Regular Contents: Dissecting the Web Hosting Ecosystem

Abstract

Ads (advertisements) have become a common source of revenues for websites and transformed the web hosting ecosystem. This paper reports an extensive measurement-based study of web hosting with an explicit focus on differences in the hosting of ads versus regular contents. Using a VPN (Virtual Private Network) service and 22,040 open recursive DNS (Domain Name System) resolvers, we collect contents of top country-specific websites in 52 countries around the globe and characterize the hosting infrastructures. While we observe that ads employ more servers for broader load distribution, replication is local for ads and global for regular contents. Our results clearly show that transit ASes (Autonomous Systems), including the tier-1 networks, diversify their economic roles and prominently provide web hosting. A small number of ASes dominate heavily in the byte volume of hosted contents, with the top hosts being different for ads and regular contents. Compared to ASes and organizations, the distribution of hosting countries is even more heavily skewed, with the USA consistently taking the overwhelmingly dominant position. While ads have shorter response times, their download times are longer because websites are developed to serve requests for regular contents with a higher priority.