Donna Summer really gave dance music it's "face".
Think about it. Back in 1975, disco WAS rising but for the most part it was still an underground sound. There WAS a disco station then (WPIX - Disco 102) that played the format but they didn't stick with it for very long. Out comes this woman who really captures everyone with "Love To Love You Baby", a track that was VERY risque for 1975 yet somehow made it on the radio.
However, it was "I Feel Love" that really catapulted her into the music scene and soon after disco became part of the mainstream as disco stations (such as WKTU) sprouted up and did well. More disco tunes came through and artists that were traditionally rockers got into the scene (Rod Stewart, Rolling Stones, Queen) as well as balladiers (Bee Gees).
Her influence is the reason that dance music exists.
A BIG LOSS
