Chapitre d'ouvrage: Individuals interact through social media networks by posting contributions, comments and the like. These actions entail complementarities and generate spillovers. A social media carefully designs its platform, often with the objective of increasing users' activity. Here I study visibility strategies, which promote some individuals by making their contributions more visible than others'. Under some specifications, optimal strategies are simple, making visible the individuals whose total impact (total number of followers for example) is maximal. Comparisons with other targeting strategies are discussed.