In the digital domain, users can be expected to place their trust in online services if they have a reason to believe that, in addition to the functional and quality of service aspects, their rights will be protected and their shared values respected. However, recent studies and surveys suggest that users do not actually trust in online services, one of the reasons being that technology unable to meet their values and address their concerns. To bridge this gap, this work-in-progress paper presents a set of core areas of trustworthiness for online services that have emerged from an interdisciplinary discussion involving a social, ethical, legal and technological perspective while paying due attention to the protection of European fundamental rights and values. It then analyses the manner in which each of these core areas of trustworthiness maps to well-known system properties and (post-compliance) operational requirements.