With the Cambridge Analytica scandal, it became clear how technologies such as social media and techniques such as psychological profiling can be combined in election campaigns with worrying effects. Personalised political messaging is highly automated. It starts and ends with social media, which provides both the data for categorising users and the medium for targeting them with personalised messages. Messages might be designed to favour a particular candidate or to encourage widespread discord and mistrust. In either case, it could lead to more polarised societies in which citizens share less common ground and are less understanding of those with different political ideologies, attitudes to populism, or perspectives on specific topics such as immigration. These same technologies and techniques also shape trends in news production and consumption. As newspaper sales dwindle, outlets increasingly rely upon ad-revenue generated by clicks, making extensive use of social media platforms and user profiling. Public debate increasingly occurs via these social media platforms in which citizens, politicians, companies and bots communicate directly to each other without the traditional filters of journalistic standards and editorial oversight. It has been suggested that, where citizens increasingly rely on such platforms for news, they risk entering so-called ‘filter bubbles’ in which they are exposed to a narrow range of perspectives oriented around their own profiles, shielded from contrasting views, in a broad trend that could also lead to more polarised societies. In this context, STOA launched two studies to explore the mechanisms by which these technologies and techniques may foster polarisation in Europe. One study approached the question with reference to trends in the production and consumption of news media, while the other focussed on trends in political campaigning and communication strategies.