Moving up the charts
With costs of producing an album, promoting it, going on tour, and everything else that is involved, a musician has to sell a lot of music in order to make money. Selling more CDs means more touring opportunities, and more touring opportunities means selling more CDs and getting more airplay. It becomes a cyclical thing that feeds on itself: charts are based on airplay and records sales; record sales improve with more airplay, which keeps the song on the charts.
However, with Billboard's shift in ratios, weighting record sales lower than airplay, the key to staying on the charts is now staying on the radio.
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