I usually don't buy content from Apple. I bought some iBooks, only to later find out that these can't be opened on other platforms.
Now, I want to buy some music, and I wonder where I should buy it from. I may buy from iTunes, if it allows me to transfer and play songs on other platforms at a future date.
I usually just buy content from Amazon, at least with Kindle, they allow you to enjoy your content across various platforms. So, I also wanted to know if it is possible to buy songs from Amazon and play them on iPhone from iPhone's music app. I downloaded Amazon's music app, but it does not have any songs. I know that's weird, but the search didn't show any of the songs I searched for, and they were all popular songs.
So, really, given that I want to platform-proof my musical content, and yet play it on the iphone, where it should I purchase it from?