But the biggest player in this future isn't one of the names most associated with streaming — Spotify, Amazon, Pandora or Apple. It's YouTube, the site best known for viral videos, which accounts for 25 percent of all music streamed worldwide, far more than any other site.
Now, YouTube is locked in an increasingly bitter battle with music labels over how much it pays to stream their songs — and at stake is not just the finances of the music industry but also the way that millions of people around the world have grown accustomed to listening to music: free of cost.
Music labels accuse YouTube of using a legal loophole to pay less for songs than traditional music-streaming sites, calling YouTube the biggest threat since song piracy crippled the industry in the early 2000s. The industry has pressed its case to regulators around the world in hopes of forcing a change.
"I do think YouTube is starting to panic a little bit," said Mitch Glazier, president of the Recording Industry Association of America.
But YouTube is not backing down, stressing the benefits to musicians of promotion on one of the Web's most popular sites — which allows ordinary users to integrate music into their uploads. YouTube also warns against attacks that could reduce competition among streaming services.