Underground music comprises musical genres beyond mainstream culture. Any song that is not being legally commercialized is considered underground.
Underground music may tend to express common ideas, such as high regard for sincerity and intimacy, freedom of creative expression as opposed to the highly formulaic composition of commercial music, and appreciation of artistic individuality as opposed to conformity to current mainstream trends. Apart from perhaps the underground rock scenes in the pre-
Some underground rock bands never got non-mainstream roots. They are radical, aggressive 60s bands such as
... now transmitted laterally and collaboratively via the internet. You once had a series of gatekeepers in the adoption of a trend: the innovator, the early adopter, the late adopter, the early mainstream, the late mainstream, and finally the conservative. But now it goes straight from the innovator to the mainstream.
In effect, this means a