No matter my goal, I found that my Pandora stations always converged on the same endpoint. I always ended up with Ellie Goulding and Dubstep, despite not really liking either of those. It rather killed my interest in the service.

The one exception was an experiment where I gave every single song a thumbs up. It converged on comedy rock (Weird Al, Tenacious D, Flight of the Conchords, etc).

Way back when I used Pandora I found similar behavior if I gave songs thumbs down. It would converge on a small selection of a few artists and their music. It was really good at some genres if I didn't thumbs up or down many songs.

I've seen the same kind of thing in other services that weight recent choices as a part of their graph based recommendations like Spotify and YouTube. They can get stuck in a feedback loop where the pool of recommendations shrinks to the point where it recommends the same stuff over and over.

That isn't a feature of Pandora.

I have quite a few channels:

1. Comedy rock, seeded by "Code Monkey". (Mainly Jonathan Coulton and Weird Al Yankovic, but other people sneak in there. The biggest hit, in personal terms, was a song by Matthew Ebel.)

2. Secondary comedy rock, seeded by "Weird Al Yankovic"; this channel is mostly dead. It tried to converge with the main comedy rock channel for obvious reasons.

3. Country (sad), seeded by "She Used To Say That To Me". The main thing on this channel that I personally see as a genre outlier is Mark McGuinn's "Busy Signal", but going to youtube I see that that song is tagged "#countrymusic".

4. Country (happy), seeded by "Emily Harper".

Those two channels also constantly attempt to converge with each other. But they mostly don't try to converge with the comedy rock channel.

5. "Clancy Brothers".

This has blossomed into a more general Irish folk and sea shanty channel.

6. "Steeleye Span".

This one plays Steeleye Span and some other English folk and folk rock music. It constantly tries to play Irish music, though the Clancy Brothers channel does not try to play English folk.

7. "Alan Menken". This one is good at staying separate. It plays showtunes. (And sometimes branches out a little; Annette Funicello's "Pineapple Princess" is on there.)

8. A channel seeded by "Kiss Me", by Sixpence None The Richer. I like the way this song sounds. I was never happy with anything that played on this channel and it's been abandoned.

Within the past several years I have gotten the feeling that Pandora would rather I just have one channel that plays "everything"; there have been attempts at crossing the deeper channel boundaries.

I have never ended up with Ellie Goulding or Dubstep.