Hey @Pietras95 - good question! My degree is partly in media, so I couldn't resist replying. It can be quite fun to figure out what a company's target audience is, without asking directly. ;-)
You just need to ask the right questions and look at what images/marketing/design we use suggests about who we're aiming at.
For example, head to www.spotify.com. What do the images we use there suggest? Are the people old/young? Where are they, e.g. at home, on holiday? What are they wearing? Then try to think why we'd show people who are listening to music at home - are we targeting people who spend a lot of time at home, e.g. people who don't have jobs?
At least one person is using an iPad, so that suggests we're targeting people who can afford/want to use iPads - would that be students? Parents? Teenagers?
We also use a bunch of different album covers on that website homepage - what can you tell about those? Do we only show albums from the last 10 years? Is it all in one genre/music style?
One of the things that page points out is how social Spotify is - you can Follow friends/artists, share with Facebook/Twitter/blogs - so you should ask, "what kind of people want to share music like that?"
That's all just from one page on our website. You can also check out our blog or Facebook page. Who'd be interested in reading the kind of content we share there?
I'm not telling you the answer, just pointing you in the right direction to find one. There's so much you can figure out with so little actual information. :-)
I recently did a presentation on Spotify too, and my group mate found this information (not sure whether it's accurate or updated) that 80% of Spotify users are 35 years old and below. Also, check out Spotify's brand guidelines (somewhere on the Spotify's website), it provides the characteristics of the market that Spotify aims at.