ed
The fact remains : No man is an island. You will always be influenced by somebody elses music/riffs, and I am sure the artist was influenced by another musician etc. But plagarism becomes more evident when an entire riff or idea is based on something that you did not create. I mean none of us play our OWN riffs. We're always practicing someone else stuff. So plagarism is basically the case where, a song or riff is copied without acknowledement. You cannot say that if your music or idea triggers something great in somebody elses mind, that it is plagarism.
singemonkey
I feel like it comes down to using a complete thought. Consider:
"To be or not to be? That is the question."
Using this line as your own is plagiarism
"To be or not to be? Ah. Who gives a crap?"
... is a reference.
Or, "It was the best of times. It was the worst of times."
- plagiarims
vs. "It was a great age. It was an evil age." is merely inspired by the first.
Same with music. To use part of a riff - a chord sequence but a different melody, the first part of a melody with a different resolution - this is fine. Natural. But a melody played slower, a bridge played faster, this is plagiarism.
Strangely, I don't think it counts for drummers (what does? ?). How many people have used John Bonham's "When the Levee Breaks" with impunity?