Public Access ICT across Cultures: Diversifying Participation in the Network Society (MIT Press); Social Media in Southeast Turkey, Social Media in Northern Chile, Social Media in Industrial China, Social Media in Rural China, Social Media in Southeast Italy, Social Media in South India, Social Media in Emergent Brazil(this latter volumes is due out in October 2017. They and others to follow are all part of the Why We Post ethnographic project tracing the use of social media in various communities around the world. The volumes are published by the University College London Press.) Also, look at Anthropology of Social Networking, a directory of research projects.
Anthropological Research on the Use of Social Media