Social media and mobile technologies have revolutionised communication and particular attention has been given to user-generated content (UGC) and the formation of online communities; however, little attention has been given to tourist events entirely generated by users through social media. This paper aims to define and characterise the phenomenon of tourism user-generated events (UGEs) through social media around the user’s new empowered role and to assess user-generated social media events’ online socialness. It is also our aim to provide a useful mixed-methodology analysis framework for UGEs in relation to social media and to highlight their interest for organisations. The methodological approach includes a quantitative model to store, analyse and compare events’ online socialness, which is combined with qualitative, participant observation at the events. This approach is applied to the analysis of three Instagram meetups organised by a specific online community at Catalan ski resorts. The paper’s results show the differential characteristic of tourism UGEs: user initiative and empowerment, full organisation and structure, great social media use and UGC production, brand dissemination, attraction capacity, strong online community bond and faithfulness. With UGEs, an event management paradigm shift occurs as organisations are no longer the main initiators and controllers of the event.