This book aims to establish a foundational understanding of the prohibition of self-favouring by digital gatekeepers as stipulated in Article 6(5) of the Digital Markets Act (DMA). It elineates current concerns while offering guidance for effective compliance.

Until now, little attention has been paid to the intricate interrelations among online search engines and other digital services. This book seeks to elucidate this landscape, delineating, in particular the boundaries between online search engines, online intermediation services and online information services that designated gatekeeper need to consider when designing their systems to comply with the DMA.

Article 6(5) targets 'platform envelopment' strategies that detrimentally impact consumers and businesses. The core concern is the presentation or the direct offering (i.e. embedding) of distinct services on the results pages of an online search engine. Such practices are permissible only if third-party providers of a similar service are afforded an equal opportunity for presentation or offering. Equivalence necessitates that no imbalances in rights or obligations remain and no disproportionate advantage in conferred on the gatekeeper's embedded first-party service, its online search engine or any other core platform service.

This book sets out precise legal guidelines for achieving compliance with these obligations.