At least for the desktop software, they detect if you turn the volume down quickly, and pause the commercial. Spotify has pretty rude behavior towards their free users, but I suppose they want to push everyone to subscribe.
I think it's pretty telling that comments surrounding an article about artists not complaining about getting paid enough people complain about the only method Spotify can implement other than charging you money for the service.
It's not a rude behavior and is within their right when you utilize their service for free.
Commercials/advertisements are fine.
Allowing over compressed, perceivably louder sounding commercials on their system is annoying.
Recognizing that people hate this and trying to prevent people from turning down the volume in reaction to a jarring change in sound is rude.
Being rude to your free users in order to get them to upgrade is a strategy that works (nagware), but is it a better than other strategies?
I use the (I think still considered "beta" or something) Linux desktop version and it does not know when I turn the volume down.
When commercials come on, I quickly mute the machine, and I get a nice popup with the next song title to let me know commercials are done.
It's nice because I find radio commercials particularly obnoxious--far more than television--and spotify will sometimes play them back to back.
Speaking of which: their radio algorithm must be broken. I can select an entire genre--say classical music--and start getting repeats within a couple of hours.
They just don't have much music. I tried spotify as a youtube substitute a few months back (at a friends house). Turns out they don't have a single song I searched for (all available on youtube, well known genre classics).
It really depends, probably on the labels concerned. My own short, happy, musical career is documented in full - that is, eight tracks on obscuro progressive house labels from 2008-2011. Nobody will ever want to listen to them, except me.
(I never saw a cent, but since they're all diplomatically categorised as '< 1000 streams', that would add up to one laughable payday: and besides, I never saw a cent from the labels either.)
I know a lot of older house/trance etc tracks, including genre classics, are stuck in licensing hell after the labels folded, and I would expect that to be the more true the further back in musical history you go.
If I get back into things, I'll probably just give the MP3s away. There's no money in music, and I earn a living elsewise.
I don't have this problem in the genres I listen to--they have only not had a couple of songs from pretty obscure groups.
Even when I create a station by artist, say The Avett Brothers (considered folk music, I believe), I end up getting repeats quickly--even among the non-Avett artists playing on the station.
My own personal folk playlist (on spotify) has more variety than their own station.
I'm convinced it's an algorithm issue in my case. In yours, possibly lack of choices.
Good luck for them to detect that my external speakers are unplugged or that my external audio interface analog volume knob is turned all the way to 0.
or just plug in (cheap) headphones, now spotify thinks you're listening, the music is actually playing and you can physically see why when you try to play something else it doesn't work. Everyone wins!