Streaming has quickly become the way much of the world listens -- and its also becoming a path to the stratosphere for artists.

The world's largest subscription service has been called a new form of radio, a musical buffet table and every music fan's must-have app. More often than not, and right or wrong, Spotify is called a threat to the record business. With its freemium business model -- a free service and a paid, premium service -- Spotify gives people an on-demand service good enough to easily displace on-the-margins purchases. This means discovery hard currency to a subscription service.

Discovery is the ability to turn people on to an artist or track -- the right track to the right person at the right time. It can help make a good service a great service, and it's the goal of all to offer robust avenues for discovery. A success story earns bragging rights for a breakout artist or track.

The thing is few services can actually move the needle. Spotify is one them. A large user base isn't enough, however. A streaming service needs the right levers to pull.

The stories behind Hozier's "Take Me To Church" and Major Lazer's "Lean On" are about pulling those levers to reach the top of the platform. "Take Me To Church" was one of the most popular songs of 2014, Major Lazer's "Lean On" has been one of 2015's hottest tracks. Both reached the top of Spotify's global chart. While each took a different path to success, they both have one thing in common: Spotify lent a helping hand.

MAJOR LAZER GOES MAJOR

Spotify's decision to back "Lean On" was driven by data. "The data is everything," says Steve Savoca, Spotify's head of content. "We don't do these things unless our users are telling us there's interest." Streaming data allows Spotify to target songs it believes can break into its global chart. It wants songs that will turn listeners into fan advocates who save the song to playlists and listen repeatedly, explains Savoca. "We can program it as much as we want, but the idea is we have to convert that programming into adoption, saves and plays."

"Lean On" was released globally in March. By May the track was closing on the global number one position. At the time, the difference in daily streams between "Lean On" and the top global track was 800,000. Spotify took notice and wanted to help push it upward. It started collaborating with TMWRK, the management company that represents Major Lazer and its principle artist, Diplo) to push the track to number one.

Many of those aforementioned levers were subsequently pulled. According to Schlosser, Major Lazer received about 20 home-page takeovers -- banner placement in the "browse" section of the premium service -- in 18 different territories. A microsite for the Mad Decent Block Party, a tour created by and named after the label Diplo co-owns, encouraged people to listen on Spotify and share tracks on social media to win tickets.

Those high-profile promotions notwithstanding, inclusion on Spotify playlists was key, says JT Myers of mtheory, a marketing strategy and operations team that works with TMWRK. "Spotify controls many of the most-subscribed playlists. That's one of the key tools." To reach playlists not owned by Spotify, m-theory worked with Nashville-based digital promotion company DigMark.

The combination of promotional channels paid off. "Lean On" had about 2.5 million streams globally in May. A two-week push landed "Lean On" atop Spotify's global chart from the weeks ending May 31 to July 30, with fans streaming the song 38 million streams during its reign.

By most measures, "Lean On" was already a success by the time Spotify lent support. Diplo's team started by building up followers to the "Diplo and Friends" Spotify playlist, a curated mix of tracks by Diplo and other artists, from 30,000 to 138,000 today. People weren't just hearing Major Lazer, says TMWRK's Kevin Kusatsu. After discovering the track, people would look for Major Lazer elsewhere on the platform: the artist profile, and playlists it's featured on. "I think that's more about participating in the product."

"This isn't the first time Diplo and Major Lazer had something that got action on Spotify, so we expected to see something on the Viral 50, or something like the things you would typically see if you do things the right way," says Myers.

"Lean On" was "sticky," says Katie Schlosser, director, Label Relations North America. Spotify could tell from the track's appearance on the viral chart that listeners were sharing the track -- an indicator also seen with "Take Me To Church."

"It was our users that alerted us to the fact something was going on," says Schlosser.

HOZIER, FROM THE EMERALD ISLE TO EVERYWHERE

?Hozier had little momentum and activity when Spotify first got behind him. "Take Me To Church" was a slow burn. It was first a hit in Hozier's native Ireland. According to Shazam data shared with Billboard, "Take Me To Church" started picking up in late August 2013 before spiking the following month. Daily Shazam activity peaked in late October, less than a month after people started showing interest, and gently faded into spring.

The Irish rocker was inducted into Spotlight, an artist development program Spotify launched in October 2013, without a back history that could offer clues to his potential. Over time, daily plays of "Take Me To Church" would steadily rise for nearly a year until hitting a sharper, upward trajectory. A final push from Spotify would give it even more momentum.

Daily global streams spiked from about 15,000 to 30,000 when Spotify announced the 2014 Spotlight artists. "Take Me To Church" saw another spike, albeit to a lower peak, when Hozier was the subject of a home page takeover in the United States. From Dec. 5-19 of 2013, 24 percent of all "Take Me To Church" streams came from a playlist dedicated to the 2014 Spotlight artists. It hit No. 7 on Spotify's Global Viral chart at the end of March 2014.

"Take Me To Church" looked like a hit in August. The song reached #1 on the AAA chart in the U.S. in August, coinciding with Spotify adding "Take Me To Church" to its playlists in earnest. Daily streams were nearly 200,000, but only 3 months would pass before "Take Me To Church" would be steamed 2 million times daily.

October was a huge month. First came the album release. "Take Me To Church" was Top 5 at alternative radio in the U.S. Two weeks later it was in the top 40 airplay chart. Then, in the early days of November, "Take Me To Church" hit No. 1 on Spotify's US chart. This is when Spotify decided to give "Take Me To Church" an extra lift.

Starting in mid-November, Spotify's undertook a campaign to push "Take Me To Church" to the top of its global chart. The song reached No. 3 on the global daily chart after being aggressively added to Spotify playlists. It reached No. 1 on the daily global chart after being added to the "Today's Top Hits" playlist. There was, like Major Lazer about two dozen months later, a series of home page takeovers, inclusion in a global Year In Review campaign and inclusions in social postings and newsletters. Twelve days after the "Take Me To Church" campaign began, the song reached No. 1 on Spotify's weekly global chart.

Would Hozier have reached number one without Spotify's help? Spotify doesn't believe so. It calculates the incremental impact to be three million streams over four weeks. To be fair, Spotify's impact was probably less, considering Universal Music Group added the song to its Digster playlists, gave it support through other promotional channels and got the song increased airplay at U.S. radio.

Nevertheless, Spotify seemed to make the impact it wanted. Daily plays of "Take Me To Church" climbed at a faster rate once Spotify gave it an additional push, and over the course of the Spotlight program, Spotify introduced Hozier to 11 million new listeners worldwide, according to data supplied to Billboard. The editorial impact was huge: 46 percent of all discoveries on the service happened on Spotify playlists or the Browse section.

The influence of playlist additions alone is huge. Spotify's most popular playlist, "Today's Top Hits," currently has 5.8 million followers -- roughly one out of every 13 monthly listeners. Prioritizing "Take Me To Church" on such a playlist can propel a song forward. Major Lazer's "Lean On" fits right into a playlist like "electroNOW," which has 1.5 million followers. When people listen to a playlist, they often add it to their own playlist and listen repeatedly. Listenings of those playlists might add some songs on their own playlists. This is how music becomes viral within a streaming platform.

BIG OR SMALL?

Who might benefit from a push at Spotify? It helps to be signed to a record label. It helps even more to be on a major label. Self-released, independent artists aren't automatically disqualified, but like so many other areas of their careers, they'll have to create their own momentum before the industry takes notice. It shouldn't come as a surprise that artists with strong labels, publishers, managers and agents are the most likely to find popularity on streaming services.

Twelve of the current 18 Spotlight artists are signed to major labels. Mikky Ekko has enjoyed a long buildup to his debut on RCA Records -- he was featured on Rihanna's 2013 single "Stay." Børns is signed to Interscope Records. Leon Bridges and Raury both released their debut albums on Columbia Records. Artists with global companies behind them stand a good chance to bubble up to the top of the charts.

But Spotify is putting its weight behind indie artists, too. Houndmouth is signed to Rough Trade Records. MisterWives is on New York indie label Photo Finish Records. Rapper Pell has self-released his music (he is signed to the ICM Partners agency). Rockers The Bohicas are signed to Domino Recording Co. Norwegian singer Aurora is signed to Universal-owned Decca Records and Glassnote Records, the independent label behind Mumford and Sons and Phoenix.

To its credit, Spotify is democratic platform. Independent artists might have a difficult time getting the attention of Spotify's decision makers, and they may not get either the exposure or momentum of label-backed artists, but they're not automatically removed from contention. "Lean On" is notable because it was the first independent release to hit the top of Spotify's global chart. The song, and its album, was self-released with mtheory. The parties partnered with Because Records for the rest of the world.

An obvious question is why Spotify wants to get behind certain artists. Did Spotify start playing gatekeeper to prove its value to the industry? It would certainly benefit a subscription service -- especially one so often maligned -- to be perceived as a creator of both careers and royalties rather than a destroyer of an industry. Does Spotify want to support artists and help them improve their careers? That is to say, does the company see supporting musicians as a fundamental part of its mission? Or does it want consumers to associate Spotify with the discovery of the next big thing?

The answer is all of the above. Spotify wants to be seen within the industry as a launch pad for developing artists. Savoco explains that Spotify believes it can create long-term partnerships with artists. Perception to listeners is also a factor. There's a desire for consumers to think of Spotify as a place to discover the best of the dozens -- if not hundreds -- of new artists clamoring for their attention at any given moment.

But Spotify also wants to help artists build careers. Savoca can understand the need to develop artists. He came to Spotify from Domino Recording Co., an independent label that helped build the careers of Franz Ferdinand, Caribou and Animal Collective, among others. Many of Spotify's employees come from the traditional music business that revolves around finding and breaking new artists. "It's what gets us out off bed in the morning," says Savoca.