Well,
I can clear up the artist's right question for you. Artists like Dylan and Clapton had the decision to say "yes or no" to having those songs used in commericals. They copyright each song they write. Hendrix and Lennon's songs were sold to the respective advertising companies by the people who bought or inherited the ownership of those songs. Jimi Hendrix's family won a law suit giving them full ownership of Jimi's work. The John Lennon songs were initially bought by sony and sold to anyone who had the money to buy them (i.e. pepsi) Most of them were subsequently bought by none other than Michael Jackson, who won a lawsuit filed by Paul McCartney, who wanted to win them back. (he wrote a great deal of them and sold them back when he had alot less power).

To GIOK:
I'm not saying I disagree, but why do you think Bob Dylan sold out years ago?

-Spartacus