Have You ever had a moment when You listen to the music and suddenly You say: "Oh I've already heard this song or part of the song"? Many times I had that feeling of pseudo deja vu. I was wondering what causes that until I started to dig very deep into various music genres during my first steps in a music production process. Then I realized what "Sampling" was all about. Sampling is a creative process of cutting a part of the song and transform it into Your own composition based on the roots of original audio track. Sometimes it might be a whole melody, and sometimes it could be only one word or sound. This is particularly common practice for Hip Hop music producers.
Some might say it's a stealing but for myself it's quite simple. If we use a part or a tiny little piece of other's masterpiece why we shouldn't? Is it so bad to re-create something which is already out there and make it to some other great piece of art? The answer is clear:) Very good speech about this topic was made by Mark Ronson - UK based producer. He explained the origins and described a whole process from sampling to producing.