Guidelines for Mobile Web Content Adaptation by Third-party Proxies

The Mobile Web is a world of constraints: limited memory, limited screen sizes, limited input methods, limited availability of the user on the go, high latency and low bandwidth networks. Some mobile network operators deployed Content Transformation solutions onto their mobile networks to give their users access to the "long tail" of legacy Web pages that were designed for desktop browsers and that do not render well on mobile devices. Content Transformation is actually envisioned both as an extension set of functionalities to mobile devices browsers and as a way to improve the overall user experience while browsing the Web on a mobile device. In practice, Content Transformation done by third-party proxies creates a number of issues that threaten the Web neutrality and in some cases break the actual delivery of Web content to end users. The W3C is working on a set of Content Transformation Guidelines to ensure that the impact of conforming deployments on the mobile ecosystem stays positive. This paper presents the potential and limitations of content transformation when carried out by third-party proxies, and how the guidelines proposed by the W3C Mobile Web Best Practices working group intend to solve the issues created by existing solutions. The work on the guidelines is on-going and some guidelines may change in the future. The work already helped identify potential topics for future works, in particular the need for explicit semantics that could be used by content providers to tag their content and communicate their intent and expectations with Content Transformation proxies.