If you listen to some songs off track it will ruin the recommendation engine for a long time with Spotify. E.g. child music is the most obvious one. Having a party with people choosing songs ruins it.
So in practice it is not very user friendly since you can't pause it.
I'm not sure this is a good solution; it violates multiple UX principles around the ability to undo, to see what a program is doing. It's also bundling a lot of stuff together in an unintuitive way: "Incognito" (or as Spotify seems to call it, "private") listening doesn't signal that it has anything to do with recommendations, and if you turn it on I believe it also does things like block social features.
I don't think "private mode" in applications is a good alternative most of the time to more direct controls like:
- An opt-in mode for training the algorithm.
- An ability to after leaving a phone on overnight to clear a bunch of songs out of your recommendations.
- An ability to mark a song that you like as irrelevant without blocking it.
- An ability to import and export recommendation lists and then to "pause" or "freeze" your recommendation training.
- An ability to freeze/fork/revert your recommendation profile.
- The ability to have multiple recommendation profiles.
- etc...
Going into a special mode to preemptively avoid a program from acting unpredictably and doing unpredictable things is bad UX, we should just call it bad UX. One of the big reasons that bad UX exists is because companies aren't using recommendation algorithms to benefit the user, and so they don't want users to be in control of them or to be able to easily turn them off or tune them. The recommendation engines are there to push Spotify's interests even when those interests don't align with the user. Bad UX and bad recommendation controls are in some ways a feature for the company, not a bug.
If the recommendation engine was presented in a way that consumers could easily control and if the majority of even casual users felt confident interacting with it and regularly turned it off, then that would be treated as a software defect to be fixed. Modern recommendation UX has more in common with advertisements or the popups websites put in front of content to force you to make an account, in the sense that you're not really supposed to take advantage of any opt-outs that the companies begrudgingly supply.
The problems you describe are why anything "algorithmic" is hated in some circles, despite there (IMO) being value in it in theory. People just can't imagine it ever being good because in reality it almost never is.
Also you can right-click a playlist and select "Exclude this from musical profiling" (translated from my native language). I did that for many older playlists I'm no longer into, and this seemed to cause a significant steer in weekly recommendations which have since turned to be much more in line with my current tastes.
Spotify should still be able to realise when something completely outside of the normal is played. Maybe as a different listening mode, eg "Kids party" - and keep them separate.
I had no idea this existed, nor would I know how to turn it on from Google Home / Alexa, which is my primary consumption method (particularly in "party" circumstances).
So in practice it is not very user friendly since you can't pause it.