Expansion of Music Media
Sound recording was invented in the early 1800s. Unfortunately, no one could figure out how to play back recorded sounds until Thomas Edison invented the phonograph over 70 years later. Even after Edison's marvelous discovery, it took the innovations of many more inventors to find affordable ways to copy recorded material.
As recordings became more affordable, the market grew and the record business became a moneymaker for publishers and songwriters.
The Radio
The next important step was the invention of the radio, and it's still debated as to who invented it. Certainly, Tesla, Marconi, De Forest, and several others all deserve some credit. The first commercial radio stations began to spring up around 1920. Within a few years, radio had become an important part of the music business, presenting the opportunity for a single performance of a song, live or recorded, to reach millions of people.
Radio also spawned a new and profitable genre, the jingle, a short song that advertises a product. Jingles are good for songwriters in two ways: Songwriters make money for writing jingles, and revenues from airing jingles and other commercial advertisements are the main source of income for radio stations, which pay performance royalties collected by songwriters.
Affordable audio copies and broadcast performances suddenly made songwriting a potentially profitable profession. The Copyright Act of 1909 gave songwriters a whopping “two cents per copy” royalty to split with publishers. Soon thereafter, the American Society of Authors, Composers, and Publishers (ASCAP) began collecting performance royalties from radio stations and live venues.
Movie Soundtracks
With the advent of movies, a new chapter in music history was born. Early movies didn't have sound, but some theatre owners began having organists or pianists play along with movies to spice things up. Eventually, moviemakers started commissioning scores to be written for their films, recording them onto disks, which were then played on a separate machine. When movies with sound were invented, some songwriters made whole careers of writing songs and soundtracks for movies.

