This chapter deals with characteristics of digital markets. It explains the functioning of multi-sided platform markets and presents different approaches to categorising digital platforms. In light of concentration tendencies in platform markets, the focus is on network effects and one-sided pricing structures. This chapter also discusses the competitive relevance of data. It outlines that access to and control over data can create advantages for undertakings and influence competitive conditions. Finally, it shows how the deployment of AI as business tool may shape market structures and pricing. It addresses phenomena, such as tacit collusion, as well as price personalisation and price dynamisation. This chapter provides brief overviews of other regulatory approaches concerning platforms (e.g. Digital Services Act), data (e.g. GDPR, Data Act, Data Governance Act), and artificial intelligence (e.g. AI Act).