Societal and technological progresses have created a multitude of new ways for people to engage with music, and as a result music can nowadays be learned from an ever-expanding variety of sources. In this article, we engage in a theoretical exploration of the underpinning societal forces that have enabled this expansion, as well as its significance for the development of musical identity and knowledge. The exploration proceeds through sociological theories of modernity and theories of sociocultural learning. Examples from a recent ethnographic study of the Finnish online music community "Mikseri" provide insight into how musical identities can be constructed and maintained in web-based reality, as well as how online music sites may function as communities of practice where the members, through sharing and discussing their own music, develop music-related knowledge. A discussion about the implications of the current media-musical situation for music education practice and research is provided. (Contains 7 notes.)