Is writing one's own music (which Peaches does, frex) in itself a meaningful analysis here? I'm not sure I get the difference in abstract, only in terms of artistic control. Why is an artist who gets someone to write their lyrics fundamentally different from an artist who gets someone to play bass for them? They're both contributing here. Britney, for example, has commissioned writers to produce some pretty explicit stuff about her own life (or is it? Is stuff like "Toy Soldier", or "Piece Of Me" just part of the image? And if so, what do we make of her cover of "My Prerogative"?) - is this any more superficial than any other joint musical venture? Can only singer-songwriters truly express their feelings through the medium of music?

(On the writing point, Cathy Dennis is a well-known writer of v successful pop songs, and was briefly a very small pop star herself. Does being the writer make her the performer, or is Kylie or Britney the performer? Or is it a gestalt?)

The Sugababes are a good example in terms of what constitutes originality in pop when someone else is involved, considering what a hit "Freak Like Me" was for them. Gary Numan reckoned he loved it, which is hardly surprising as he must have made a few quid out of it!