Clay Shirky has an interesting article about the ways in which file sharing software has evolved as a result of the pressures put on it by the RIAA and friends, and what steps that evolution might take next.
He makes the good point that this pressure has very little effect on the widespread availability of the most popular music, while making less popular music (where the artists could benefit the most from the exposure) not as available:
“Worse for the RIAA, the popularity of songs is wildly unequal. Some songs — The Real Slim Shady, Come Away With Me — exist on millions of hard drives around the world. As we’ve moved from more efficient systems like Napster to less efficient ones like Kazaa, it has become considerably harder to find bluegrass, folk, or madrigals, but not that much harder to find songs by Britney, 50 Cent, or John Mayer. And as with the shift from Napster to Kazaa, the shift from Kazaa to socially-bounded systems will have the least significant effect on the most popular music.”