For branding and identification it is very important that the logo and symbols of a business not to morph according to the context.
This one is not the biggest problem with Spotify, but worth mentioning. Spotify has a different icon for its Linux version. The picture below shows the Spotify logo that appears on the taskbar of Windows (left) and Ubuntu Linux (right).
Putting Linux’s logo on top of Spotify may look cool to some other Linux fans, but it’s not the best place to show off your priorities. I assume the developers at Spotify are very happy and proud of their software, that’s why they are excited to put the Tux on the logo. But that’s only a guess for the reason.
Also it confuses the users and they may ask what is different about Linux version that it should be marked like that? In Ubuntu the users rarely see Linux Tux on a daily basis (not even during system boot). Therefor there is a chance they don’t immediately recognize why Tux is added to the logo of Spotify and what it means.
Besides, Larry Ewing, the creator of Tux may not be happy about not being acknowledged. Specially because Spotify is not open source software.
Remove the Tux from the logo. It’s good for branding and identification.
Let me put it this way: Windows logo doesn’t change when it is installed on a Mac, otherwise it would look like this: ;)
PS. this page turned out to be very popular because of this Apple+Windows logo. So I made a few more. You can use it totally free.