The notion that music fits certain activities continues to spread at digital music services. Soundrop, known best for its Spotify app, launched what it calls “theme rooms” Tuesday that allow listeners to choose music based on activities. This approach to music discovery was popularized by Songza and adopted by iHeartRadio earlier this year.

Soundrop’s new themed rooms are Partying, Getting Romantic, Falling Asleep, Working, Relaxing and Working Out. The Working Room has been the most popular of the group with about 190 concurrent listeners Tuesday afternoon. Partying was the second-most popular with 59 listeners. Both figures are well behind the most popular genre rooms. Chill Out had over 900 listeners while Indie Wok, the hangout for lovers in indie rock, had over 600.
 
While other services have similar activity-based discovery options, the user-generated aspect of Soundrop's playlists is unique. The crowdsourced playlist -- people select songs, others vote them up in the queue -- is Soundrop's defining characteristic. The approach can be problematic at times, however. Is there a good reason the Beastie Boys’ “No Sleep ‘Till Brooklyn” is in the Falling Asleep room? Fortunately, a corrective measure exists for these occasions: users can flag out-of-place songs for Soundrop to review.

Music services are obsessed with encouraging music discovery, but they have different approaches. Listening to music based on one's activity or mood may introduce people to more new music than recommendations or playlists that use an artist as a starting point (the Pandora approach). Some people believe this type of approach limits the kind of music discovery that introduces people to new artists. For example, if you' like the Rolling Stones, you're likely to be familiar with most -- if not all -- artists an algorithm will select. "People have been exposed to such a tiny pocket of the musical universe, they don't know what they like," Songza CEO Elias Roman told Billboard recently.

But Soundrop still believes in using an artist as a jumping-off point. Just last week the Norwegian startup, which raised $3 million in Series A funding last year, launched artist rooms. An artist room is created when a person creates a room for a particular artist. The second person joins the room created by the first person, and so on. The company tells Billboard fans have generated over 91,000 artist rooms thus far, and in the last week the number of active, concurrent rooms has doubled.