Songwriters who became established producers of successful songs were hired to be on the staff of the music houses.

"Song pluggers" were pianists and singers who represented the music publishers, making their living demonstrating songs to promote sales of sheet music. Most music stores had song pluggers on staff. Other pluggers were employed by the publishers to travel and familiarize the public with their new publications. Among the ranks of song pluggers were George Gershwin, Harry Warren,