In 1917, there came out of Tin Pan Alley a song called "Everybody's Crazy about the Doggone Blues" (Henry Creamer - Turner Layton).  The message had Validity:  Everybody, it seemed, was writing blues for popular consumption. 
W. C. Handy had opened the flood gates.  The tidal wave of blues inundated the song industry.

Some of the commercialized blues came from men who had known New Orleans well, Spencer Williams And Clarence Williams (no relation) for example. 

Spencer Williams had his first song hit with "I Aint Got Nobody," published in 1916.  This was a number in the style and spirit of the blues.  Among his other popular hits was "Squeeze Me," which he wrote with Thomas "Fats" Waller -- Waller's first composition, published in 1925. 

Most of the blues written for the general market, however, came from Tin Pan Alley's native songwriters.

David Ewen - All The Years of American Popular Music

Mabel McConnell talks about the Carter Family, Doc & Carl,
The Original Virginia Boys and the early days of radio.-