I\'ve been thinking about this subject a lot lately. I find it pretty ironic that Joe Satriani sues Coldplay, and it turns out that both tunes resemble that Marty Balin tune. And who knows what dozens of songs that were written before that tune resemble and so on. Maybe this was a way for Joe to bring attention to himself which equals to more album sales for him.
I do agree with Tim that there are only 12 notes and coincidences are bound to happen, especially with simple, catchy melodies over diatonic chord progressions. But, I have no respect for artists who totally plagiarize other artists. Taking credit for someone else\'s work is despicable.
One example (which has been talked about in this thread) of such an act is Pearl Jam\'s "Given to Fly". I usually overlook this song because Pearl Jam is a great band with tons of original songs, but I can\'t see how this isn\'t plagiarism. Even the B section of the tune if I recall are pretty much the same. Led Zeppelin cant say shit about it because Jimmy Page was notorious for "borrowing ideas".
But there is certainly a difference between plagiarism and being inspired by an artist or band.
Musicians are usually music geeks, and musicians are influenced by the music they love. As a musician myself I have written songs or parts of songs (riffs, chord progressions, vamps....) that were influenced by certain bands or certain songs even. I remember reading that John Lennon said that "You\'ve Got to Hide Your Love Away" was totally inspired by Bob Dylan. I guess that\'s easy to see. Even the great Frank Zappa had had musical influences.