In any event, there's an interesting article at Inside Higher Ed that casts some light—admittedly, the light of an opium-den shadow play, but light nonetheless—on some aspects of fair use and copyright.
More interesting than the legal-sideshow aspect, I think, is the question of how artists deal with the situation. Imitation, allusion, parody, borrowing stray bits of melody or texture—all of this is fundamental to creativity. The line between mimicry and transformation is not absolute. And the range of electronic tools now available to musicians makes it blurrier all the time.
Using a laptop computer, it would be possible to recreate the timbre of Jimi Hendrix's guitar from the opening bars of "Voodoo Chile (Slight Return)" in order to color my own, rather less inspired riffs. This might not be a good idea. But neither would it be plagiarism, exactly. It's just an expedited version of the normal process by which the wealth of musical vocabulary gets passed around.
Scott McLemee, "Legal Jams" (22 Mar 2006). This raises some interesting questions… To begin with, what is analogous to the timbre of a deity's guitar1 in other creative contexts? Perhaps something that allows us to recognize an inspiration without actually implying similarity of meaning. e.e. cummings' disdain for capitals in blank verse—in defiance of every rule for "what poetry is" found in middle-school literature textbooks—seems a good example.
I find it rather interesting that so little controversy attaches to borrowing of "classical" or other earlier music. Some of this, of course, is founded on the poor musical education of most "popular form" musicians and even more listeners: They couldn't spot the quotation at the beginning of Procol Harum's "A Whiter Shade of Pale" (to pick one fairly random example) if they wanted to, let alone identify it… and mostly they don't want to do so. Conversely, the soto voce invocation of "Don't Stand So Close to Me" in "Money for Nothing"2 is so obvious—or, at least, was so obvious to those of us in college during the Carter and Reagan years—that anybody who pointed it out had pillows thrown at them for being so pedantic.
Then, too, there's the title of this riff, which is itself reflexive. In an homage in song to a famous mathematician, Lehrer remarked, "Remember why the good Lord made your eyes: | Pla-giar-ize."
Enough of that. Back to the salt mines.
- As my son understands the First Commandment, "For I am thy guitar god Hendrix, and thou shalt have no other guitar gods before me." In that sense, this is a pretty godly household. Of course, that also goes along with the popularity of the proto-god of punk—not the Sex Pistols, but Wolfgang Amadeus Mozart (even without relying on Amadeus as somehow definitive, there's little question that Mozart and Sid Vicious would have gotten along famously).
- It's not just an invocation; on the studio album version, Sting actually does that backing vocal. This tradition continued when "Weird Al" Yankovic did his parody version of "Money for Nothing" a couple of years later. Yankovic asked permission of Mark Knopfler to do so. Knopfler said "sure, but I get to play the lead guitar on your version, too." And he did. So, then, maybe it's better if you ask a musician to join in instead of just quoting him/her. What that says about the egos in the music industry is far from shocking.