Once an area of debate, there is now general consensus among media and social science researchers that online communities represent community in the traditional sense of the term, albeit with some important epistemological differences. If one considers online communities as genuine functioning communities situated in a legitimate cultural context, it follows that they are also valid entities that can be explored and studied. Although online communities of adult amateur practitioners of diverse musics can easily be accessed on the Internet, these communities remain relatively unexplored by music education researchers. This cyber ethnographic case study examines the informal music learning and teaching in the Banjo Hangout (BH) online music community of practice, focusing on two genres--Old Time and Bluegrass banjo music--found there. Established in 2000, the BH has 51,000 members, and, on a typical afternoon, approximately 1100 to 1300 members are online surfing the site. The Hangout has many diverse features including a media and forum archive, chatroom, links to related sites, online store, member blogs and homepages, and reviews all posted and voluntarily maintained by site members. The site also features a large online learning and teaching library consisting of TAB (an alternate notation system) archives of tunes, thousands of online videos on playing, building, and researching banjos, tune sites, links to online group lessons, member blogs, and personal YouTube banjo videos recorded and posted by members. The majority of these resources are free; others are available for a nominal fee. Participants' accounts are tales of people who need to play music and to share playing music with others, be it on or offline. Participants post YouTube videos of themselves to initiate discussion, freely adding further to the knowledge base of the community via shared and constructed experiences on the discussion forums. Through hyperlinks and posts, community members co-produce and create meaning and identity through practice in community. Further, the Hangout is also an example of a large integrated on- and offline community of adults "out there" who practice participatory music making independently of a school music culture or one based on it (for example, New Horizons programs). (Contains 22 notes.)