Classic rock is a radio format which developed from the album-oriented rock (AOR) format in the early 1980s. In the United States, the classic rock format features rock music ranging generally from the mid-1960s to the 1980s, primarily focusing on commercially successful blues rock and hard rock popularized in the 1970s AOR format. The radio format became increasingly popular with the baby boomer demographic by the end of the 1990s. Although classic rock has mostly appealed to adult listeners, music associated with this format received more exposure with younger generations of listeners with the presence of the Internet and digital downloading. Some classic rock stations also play a limited number of current releases which are stylistically consistent with the station's sound, or by heritage acts that are still active and producing new music. Conceptually, classic rock has been analyzed by academics as an effort by critics, media, and music establishments to canonize rock music and commodify 1960s Western culture for audiences living in a post-baby boomer economy. The music predominantly selected for the format has been identified as commercially successful songs by white male acts from the Anglosphere, expressing values of Romanticism, self-aggrandizement, and politically undemanding ideologies.