Digital music revenues worldwide grew at a more modest pace of 4.3%, totaling $5.87 billion and accounting for 39% of global music revenues.
Last year, revenues from streaming music services grew 39% to hit $1.4 billion.
Consumer opinion suggests that delivering ads in the traditional manner of radio is less likely to be tolerated in the streaming realm.
In 2012, music listeners in the UK streamed 3.7 billion tracks, according to BPI; in 2013, that figure doubled to 7.4 billion.
The majority of US mobile users surveyed in December 2013 said they listened to mobile music at least sometimes, and around half of that group played songs often.
US internet users were far more likely to purchase music on a computer than on a mobile device, at 50.0% vs. 27.3%.
Since peaking at $14.6 billion in 1999, the recording industry has shrunk to less than half its size, barely besting $7 billion in 2012.
Estimates from research firm IBIS World project that worldwide revenues for music will fall from $27.6 billion this year to $26.3 billion by 2017.
eMarketer estimates that 147 million internet users will listen to such content at least monthly this year, or roughly six in 10 internet users.
More than one in five Americans will listen to music on their mobile phones this year.