The earliest forms of a unique American music emerged in minstrel shows and other African-derived music, including ragtime.
The period around the turn of the century was one of deep and pervasive change in American society:
Shift from a rural to a more urban population
Rapid expansion of the mostly white American middle class
Difficult period for African Americans
The pattern that began with minstrelsy was reinforced:
The adoption of African American music by whites—often in the watered-down form of mildly syncopated dance music—was coupled with the vigorous rejection of blacks as people.
By the 1910s, many basic elements of the modern music business were firmly in place:
A pattern of fierce competition among publishing companies
Mass promotion of songs, spread across media
The dominance of a limited set of musical forms and lyrical themes