The organic growth of the web has led to web sites that exhibit a large variety of properties. We conduct a large- scale study to gain quantitative insights into the browser-side effects of the structure and behavior of thousands of the most popular web sites. We find that 50 % of web pages load more than 100 resources from more than 17 distinct hosts and make the browser process more than 730 kB of javascript.

Embedded third-party advertisements are the prevailing model on the web to monetize services or content that are otherwise provided free-of-cost to end users. We quantify the effects on browser-side resource consumption caused by advertisements and find that on pages with ads, the ads make up 20 % of all HTTP requests. Furthermore, ads lead to three times as many javascript background events that prevent the processor from staying in deep sleep mode.