In most users’ experience, webpages appear on browsers as integrated collages of text and images. As a technical matter, this content is delivered and aggregated from multiple independent servers. This includes advertising content, which is typically drawn from “third-party” servers owned by the advertisers themselves. The defendants in this case are internet advertising companies, and this suit concerns their practices in serving advertisements to the browsers of webpage visitors. The delivery of advertising content from third party servers to webpage visitors’ browsers is a highly technical process involving a series of communications between the visitor’s browser, the server of the visited website, and the server of the advertising company. In its specifics: The host website leaves part of its webpage blank where the third-party advertisements will appear. Upon receiving a “GET” request from a user seeking to display a particular webpage, the server for that webpage will subsequently respond to the browser, instructing the browser to send a “GET” request to the third-party company charged with serving the advertisements for that particular webpage. . . . The third-party server responds to the GET request by sending the advertisement to the user’s browser, which then displays it on the user’s device. The entire process occurs within milliseconds and the third-party content appears to arrive simultaneously with the first-party 5