As long as I'm still able to have a hit on the radio and sell a few albums and some tickets, I don't see that it would be worth retiring.
To give a body and a perfect form to one's thought, this - and only this - is to be an artist.
The big success stories - Facebook, Zynga and Twitter - are leading to investing in ideas on a napkin, because no one wants to miss out on the next big thing.

