Subcultures may be based on age, geographic, religious, racial, and ethnic differences. More often, however, a subculture occurs when people with shared interests form a loose-knit group with a distinctive identity (sometimes called "consumer tribes"). Members of subcultures are self-selected, and signal their membership status by adopting symbols, rituals or behaviours that are widely understood by other members of the tribe (e.g. a dress code, hairstyle or even a unique way of speaking). For example, within youth culture it is possible to identify a number of sub-groups with common interests such as skaters and bladers, surfers, ravers, punks, skin-heads, Goths, homies and others. Generally known as communities, as they create a sense of belonging to something important.