Abstract   This article offers a critical examination of the court judgements in a recent Belgian case against Yahoo!. It examines the challenges related to the establishment of jurisdiction for Internet-based services and the role that procedures of mutual legal assistance should play. Belgian law obliges providers of “electronic communications services/electronic communications networks” to cooperate with Belgian law-enforcement authorities and to handle over communication and personal data. Although the terms are derived from the EU Electronic Communications Regulatory Framework, a much broader interpretation to them was finally given by the Belgian Supreme Court. Seemingly this implies that, from now on, a US-based company such as Yahoo! is, at least under Belgian law, under a legal obligation to directly comply with an order issued by Belgian law-enforcement authorities.