The development of web 2.0 has transformed the role of tourists in tourism promotion, in relation with the development of user-generated content. This chapter is a methodological contribution to the study of user-generated content on tourist social networks, which represent the point of view of the tourists themselves. It presents methods to study tourism practices at heritage sites by analyzing images from Flickr and reviews published online on TripAdvisor. This analysis of online social networks is a fundamental tool now for the tourist observation of heritage destinations, to understand how the tourists experience and live the destination, and the meanings they give to the visited areas and sites. This requires combining cartographic analysis, statistical analysis and content analysis. We apply these methods to study tourism in Strasbourg, in relation with the extension of the UNESCO perimeter in 2018. The analysis of the geolocalization of Flickr photographs and the content analysis of TripAdvisor reviews enable us question the visibility and tourist coherence of the new perimeter, and to identify the representations attached to its monuments and sites.
