The mainstay of streaming music services is instant access to millions of songs without the commitment of a la carte purchase. But the secret sauce is discovery. Pandora  proved this with its human-powered personalization algorithm that serves up sweet serendipity with each tailored track. Rhapsody  has followed suit with social features and an editorial team to recommend tracks. Facebook lets your friends guide you. And Google Music  plans to employ staff picks to highlight exclusive tracks, free songs, and undiscovered indie acts.
Now Spotify , which has long been best for people who knew exactly what they wanted to hear when they opened the standalone player, has introduced its own set of tools to make discovery core to the 10-million-user-strong service: third-party "apps." (More on why we're putting that in quotes in a second.) Rolling Stone's Jann Wenner even showed up to the Spotify event on Wednesday in New York City to demonstrate how his premiere critics would suggest playlists via the music mag's Spotify "app." What he didn't acknowledge was that many of the songs, albums, or artists that constitute the backbone of critics' lists can't be found on Spotify. In other words, established tastemakers might bring clout (and, in Rolling Stone's case, maybe a few older users) to Spotify, but they'll also highlight the rare but essential cultural touchstones missing from the service's massive catalog.
At the event Wednesday, cofounder and CEO Daniel Ek announced Spotify was opening up the service's platform to developers, enabling a slew of third parties to build "apps" on top of it. Ek hailed the announcement as a big first step, a sign that Spotify would "become a true music platform." He showed off some promising third-party integration, including apps such as MoodAgent and Last.fm. But one of the big new categories of apps for Spotify, Ek said, would be "editorial apps," or apps that guide user tastes and offer recommendations. Spotify offers listeners access to 15 million songs--what the service never did too well was offer personalized recommendations à la Pandora.
Now, in addition to Rolling Stone, voices from the likes of Pitchfork and Billboard will offer their "apps" that essentially act as re-purposed playlists, items able to be installed on the menu of your Spotify desktop client that will keep you up to date with staff picks from top tastemakers.
Ek and Rolling Stone's Wenner showed off a few examples from the app on stage, including the "100 greatest guitarists" playlist it will feature. But if you were to pull up Rolling Stone's "500 greatest songs of all time," from the popular 2004 issue, you'd have trouble finding many of the tracks. The No. 1 song, Bob Dylan's "Like a Rolling Stone," is not on Spotify, for example. Neither are any songs from Led Zeppelin. Neither would you be able to hear the 20 Beatles songs featured on the list. And if you were on the "500 greatest albums of all time" playlist, you wouldn't be able to listen to 40% of the top 10 albums, too, since The Beatles are not on Spotify.
When I asked chief content officer Ken Parks about this at the event, he said there was a "shrinking number of bands" that were not on the service. "You picked out a corner case; that problem will get fixed over time," he said. "Led Zeppelin hasn't been putting out any records lately," Parks added.
Someone should tell Rolling Stone that .
But the same issue occurs for modern acts. Just flip through Pitchfork's staff picks, and you'll notice some jarring absences--it's hard to imagine a year-end Rolling Stone list that won't include Coldplay's Mylo Xyloto, which is also unavailable on Spotify. Billboard, which traditionally provides music rankings based on sales figures, won't be able to recommend Adele's 21, which isn't on Spotify.
For app makers, this could mean serious limits to editorial. The more services that build apps--I would expect MTV's Music Meter  and Big Champagne's Ultimate Chart  to soon join Rolling Stone--the more users will expect Spotify to match music to their curated playlists. I can't imagine Pitchfork and We Are Hunted would be willing to dumb down their recommendations, charts, and staff picks to fit the confines of Spotify's music library. On the other hand, perhaps the apps will put more pressure on labels and artists to open up their music, to gain the benefit of this press on Spotify.
In addition to all of this, as many others are already pointing out , there's little incentive here for developers to build on top of Spotify's platform. "Right now, there's no monetization," Ek said on stage, meaning, as of now, there's no paid apps or revenue sharing. That might be tough for third parties to swallow--after all, why would they develop for Spotify when Apple is boasting of the $2.5 billion its paid to developers, and when Zynga  is building a billion-dollar business on top of Facebook. For the majority of partners, the value here is nothing more than an amorphous feeling of cross promotion, which might not be enough to attract top developers to the platform.
Which is why the apps we saw Wednesday were either ported from other mobile services (SongKick, MoodAgent, Last.fm and most all of the other apps were already available on other platforms) or low quality "editorial apps" that were essentially just playlists tagged with a logo, placed in a centralized location, and disguised as "apps."
Even in their praise of the new apps, few partners could say at Wednesday's event exactly why the service was beneficial to them. When asked, one said it's like gaining access to 10 million users. But without a way to monetize that newfound audience, it's hard to imagine any benefits beyond a boost in brand awareness. After all, the third parties are also restricted to building apps for Spotify's client application, meaning the services cannot be embedded on external services or websites, at least not yet.
A lack of incentives is bad for both developers and consumers. On the developer side, it means third parties aren't getting paid for helping to build out Spotify. On the consumer side, it likely means users won't gain access to Apple-quality apps. The result for Spotify--unless it changes its incentive structure--is likely an avalanche of low-quality apps, far from the immersive experiences we're used to on iOS, Android, and Facebook.
If users generated 500 million playlists, imagine what brands will do. That means, beyond Rolling Stone and Billboard, most every music mag in the world will likely build apps, from Vice to Spin to XXL. It likely means a whole host of music websites (Hype Machine, Rap Basement, etc.) will come on too. And it likely means non-music-related brands will start making their own playlist "apps" for Spotify. Perhaps Converse will want to create apps highlighting the bands coming out of its recording studio , or Hyundai will want to show off its work with DJ Premier and Erykah Badu .
At its worst, the new service could turn off users with "apps" disguised as playlists. And it won't be good for Spotify, as many of these apps may highlight the music it doesn't offer.
[Image: Flickr user Dave Pinter ]