Towards Applications on the Decentralized Web using Hypermedia-driven Query Engines

The Web is facing unprecedented challenges related to the control and ownership of data. Due to recent privacy and manipulation scandals caused by the increasing centralization of data on the Web into increasingly fewer large data silos, there is a growing demand for the re-decentralization of the Web. Enforced by user-empowering legislature such as GDPR and CCPA, decentralization initiatives such as Solid are being designed that aim to break personal data out of these silos and give back control to the users. While the ability to choose where and how data is stored provides significant value to users, it leads to major technical challenges due to the massive distribution of data across the Web. Since we cannot expect application developers to take up this burden of coping with all the complexities of handling this data distribution, there is a need for a software layer that abstracts away these complexities, and makes this decentralized data feel as being centralized. Concretely, we propose personal query engines to play the role of such an abstraction layer. In this article, we discuss what the requirements are for such a query-based abstraction layer, what the state of the art is in this area, and what future research is required. Even though many challenges remain to achieve a developer-friendly abstraction for interacting with decentralized data on the Web, the pursuit of it is highly valuable for both end-users that want to be in control of their data and its processing and businesses wanting to enable this at a low development cost.