"We realized early on that Turntable's best feature was also a problem: everybody has to be in a room at exactly the same time," says Billy Chasen, Turntable CEO. As time went on Chasen envisioned a complimentary service that let you listen to your friends' music picks even when they're not online. Today he's launching Piki, a Pandora-like free radio service for the iPhone and web backed by your friends tastes instead of algorithms. After all, he built Turntable to quench his thirst for human-curated music and playlists, yet a lot of the people he liked the most didn't have time to DJ a Turntable room. It isn't every night, after all, that Knife Party DJs a Turntable room of 1500 listeners. "We haven't made algorithms that are good enough to replace people," he says. "They're close, but we're just not there yet. No matter how good AI gets, it's never going to be a brain."

"No matter how good AI gets, it's never going to be a brain."

The fact is, there's still no great way to follow someone's music tastes online and listen to their favorite tracks, licensed directly from labels. SoundCloud relies on user uploads, while Spotify forces users to create playlists, and Last.fm doesn't have anywhere near a complete library of tracks. Rdio perhaps comes closest, which lets you play a "Heavy Rotation" station of friends' tastes, but it doesn't feel curated enough. Piki is Chasen's sincerest effort at filling this gap in the web. If you imagine Twitter not for tweets but for songs, you'll arrive at something like Piki. In essence, Piki is an internet radio service that cues up people, not tracks, one after the other.

Once you've followed some people, pressing play begins a torrent of song "picks" from those people and even some of your own picks. Users can pick songs from Turntable's library of 12-13 million licensed tracks, upload their own track, or use a browser extension to pull a song from YouTube and other sites. Each user has their own profile composed of tracks they've "picked" or "repicked," just like how Twitter profiles work for tweets and retweets. A quick glance at someone's profile gives you pretty accurate vibes for what they've been listening to lately, and what kind of music taste they have. It's a fascinating twist on radio, seeing a friend's (or your own) profile picture instead of the current song's album art. If you're really digging someone's taste, you can turn up the "Play Frequency" slider on their profile.

If the music you're hearing isn't good, it's your problem

If you don't follow anybody, Piki cues up tracks from tastemakers with lots of followers. Within the player, you can choose tags you want to hear more of, like "indie" or "garage punk," and you can also add specific artists you want to hear more of. The funny part is that if the music you're hearing isn't good, it's your problem. In the same vein, if your Twitter feed stinks, it's on you to follow some more interesting people. "Not all analogies to Twitter directly translate," Chasen says. "You have to understand that music is different from text. The way you consume music is slow — one at a time — and that's what this experience is built around."

The most frustrating part about Piki is that when visiting a friend's profile, you can only listen to previews, and not full tracks. Naturally, Piki, like other radio services, abides by the rules laid out in the DMCA and can't let you stream songs on demand "for free." If you want to listen again to a great song you've heard on Piki, you'll have to hop over to Spotify, Rdio, or iTunes — but that's the same way things work on Pandora, so people will be used to the inconvenience. Piki may not be as immediately addictive as Turntable, but it offers a feature set that should be compelling to a far larger audience. "How do we make a better radio experience?" Chasen asks. "We're sold on the idea that you do that through people."