This void created an opportunity for the disenchanted youth of the counterculture of the 1960s and their counterparts, Hippies and Flower Children, to express themselves by playing music that was largely ignored by mainstream outlets.
Inasmuch as the format was commercial, underground sought to capitalize on the maturing of the Baby Boomers who were growing out of the top 40 radio of their youth, which was still targeting teens.
A dilemma grew because many underground artists were contractually obligated to release a certain amount of singles and FCC regulations required such songs to be 3 minutes long, or less.
In fact, the actual song "Alice's Restaurant" is the entire Side A of its titular album, coming in at over 18 minutes, making it way over the 3-minute mandate,[8] grew to fame in part because of persistent airplay from underground radio host Bob Fass,[9][10] and later became a Thanksgiving tradition on other underground/progressive stations.
This in turn led to established and new rock artists placing greater emphasis on long or experimental album tracks, knowing they would receive radio airplay.
[17] Other long-running, large-market examples included WMMR in Philadelphia[21] (credited with helping to break Bruce Springsteen),[22] WBCN in Boston, WHFS in Washington, D.C., WXRT in Chicago, WMMS in Cleveland, WEBN in Cincinnati, CJOM, WWWW and WABX in Detroit/Windsor, WZMF in Milwaukee, KQRS-FM in Minneapolis, WOWI in Norfolk, WORJ-FM in Orlando, KSHE in St. Louis, KDKB in Phoenix, KMET in Los Angeles, KSAN in San Francisco, KZAP and KSFM (102.5) in Sacramento, KZEW in Dallas, KATT-FM in Oklahoma City, and KTIM in San Rafael.
Pioneering progressive rock radio disc jockey and program directors included Scott Muni in New York,[27][28] Lee Arnold in Orlando, Tom Donahue in San Francisco,[29] and Jim Santella in Buffalo.
"Stuck in the Psychedelic Era," a syndicated program heard on some non-commercial stations, recreates the format, but rarely includes any recordings made after 1970.