by Allen Johnston,

Before the invention of the phonograph, songwriters earned income by relying on music publishers to sell sheet music and piano rolls of their songs. Even as radio and television replaced the piano in the parlor, music publishers continued to play an important role as popular singers continued to rely upon established songwriters to provide their material. (Tin Pan Alley) However, with the advent of R&B (and especially the Motown era) popular recording artists began to write more of their own songs. Since that time, the music publishing industry has taken on a less important role for singers and a much more important role for revenue growth.