Notifications are a core function of current smart devices. They inform users about a variety of events, such as new messages, comments on social networks posts or application updates. As such, notifications are the main mechanisms to proactively communicate with the user. Focusing on individual device types such as PCs and smartphones, previous work showed that notifications can be distractive and disruptive. The ongoing wave of smart devices makes it possible to reach the user through multiple devices at once -amplifying the effects of notifications. What is missing is an understanding of notifications in a multi-device environment to enable the smart management of notifications across devices. In this paper we present a system that is able to share notifications across smartphones, tablets, PCs, and smart TVs. It can further reach users through connected devices such as smart watches and smart glasses. The system currently distributes 5.3 million notifications by almost 30,000 users every day. It is not only intended to provide a holistic notification mechanism but also serves us to conduct large scale user studies to gain a deeper understanding of notifications in a multi-device environment.