Music streaming site Spotify has surpassed 5 million paying subscribers, with a million of them in the U.S., the company announced at a splashy press conference in New York today.The site, which launched in the U.S. more than a year ago, now boasts 20 million total active users worldwide. While the majority of its users partake in the service’s ad-supported free tier, the fact that a full quarter have been converted to paying subscribers will be seen as an impressive step for the company. Speaking at the event, Spotify topper Daniel Ek revealed that the company has paid $500 million to date in royalties, with half that amount having been dispensed in the last nine months. He also unveiled a spate of new features and tune-ups for the platform, most notably a social “follow” function that allows users to track what particular artists, friends or curators are sharing. Yet the most intriguing moment occurred when Metallica drummer Lars Ulrich appeared onstage to announce that the band’s entire catalog would now be available on Spotify. Seated next to Spotify board member Sean Parker, Ulrich publicly buried the hatchet with his old nemesis; a dozen years ago, the drummer was among the first, and fieriest, critics of file-sharing site Napster, which Parker was then running. Glassnote Records topper Daniel Glass also appeared to endorse the model, opining that streaming had not cannibalized the sales of Mumford & Sons’ “Babel,” which his label released in September. The conference closed with a performance from Frank Ocean, who racked up six Grammy nominations yesterday.