SoundCloud, the popular free music-sharing platform that’s helped artists like Lorde skyrocket to fame, is introducing advertisements to its service. The company said Thursday that select content creators will be able authorize playing ads beside their tracks and collect some of the revenue from those ads. The ads will first roll out in the U.S., but they’re expected to appear for international users soon, SoundCloud announced. Ads mark a big step for the music streaming service, which has struggled to monetize its vast user base that includes some 175 million listeners a month.