I think Nathaniel says it well (not best, only Colonel Sanders does that) when he speaks of Madonna and GaGa and appropriation:
"...[E]ven though Klein is shamelessly borrowing from his own past work here, the wonderful thing about Gaga is that, like her spiritual pop empress predecessor [Madonna], she's her own artist, too. This makes the appropriation palatable as well as fun... until crazed fans start giving her credit for everything...I mean even Madonna didn't invent the chameleon approach to pop stardom, though her fans, like Gagas, also tried to give her credit for it at the time...Clumsy homage/ripoff like the kind that Christina Aguilera does in 'Not Myself Tonight' when she plagiarizes both Madonna and Gaga *shudder* is not fun at all and should be looked down upon. But riffing on the work of others in a new context or with a fresh twist is totally fun and what many many great artists do."
He also points out that it was a shame Beyoncé's classic "Single Ladies" video didn't credit Bob Fosse. (Oh, and one last vent about Christina Aguilera, whom I don't hate as much as many seem to—I'm sick of hearing "Beautiful," which she crooned on one of the a.m. shows today. She sings it well and it's a classic, classic song, but so was Cyndi Lauper's "True Colors," which similarly aged into schmaltzy nonsense.)
By the way, for those who think Lady GaGa will fade out, I'd be willing to bet that in 10 years we could still make "hot like Mex-i-co and "Ale-Ale-jandro" references to approving and understanding young ears.