This chapter investigates how and why amateur musicians use social networking sites, employing a mixed-methods approach. Attention is focused on four big Italian Facebook communities of pop-rock musicians: drums, bass, guitar, and keyboard players (overall, 2,101 active users), analyzing the relational and textual data extracted from the web. The chapter analyzes the network structures emerging from the interactions among the users. It also identifies and maps the main areas of discussion (sound shaping, studio recording, marketplace, musical references, computer production, and relations) and the latent semantic dimension characterizing Facebook users’ activities, through social network analysis and lexical correspondence analysis....