Well, what we're talking about is the free samples that are often offered by artists - I think these should be alright, particularly if they're full-quality samples. It's not any more wrong to use them than the stuff available on CD, I think, although if you're considerate to the artist, you'll surely buy the CD...
And then there's cases like mine: I used a track by King Crimson called "Happy Banana Tuna" in one of my videos which right now isn't available anywhere at all, and is not on any CD. But for a time, it was up for download on one of the band members' website; and I thought it was rather fair to use it. Especially since I wanted to be obscure to the max
The Birds are using humanity in order to throw something terrifying at this green pig. And then what happens to us all later, that’s simply not important to them…
now I'm totally confused on the MP3 & Downloaded issue 
