Last year, we went to a Dar Williams concert here in St. Louis. After the concert I was kicking myself for not taking along some sort of digital recorder—a minidisc recorder or some such—because in the course of the concert, Dar sang a pair of tremendous duets with her opening act. Those versions of the song are lost, unless I miraculously find someone who bootlegged the concert.
It seems to me there's a huge opportunity here. If the artist were to have every concert professionally recorded, and the results were burned to CDs and sold at the end of the concert, you could create an entire new revenue stream with a huge bonus: unauthorized bootlegging would virtually vanish (who wouldn't shell out for a high-quality, authorized recording of the concert rather than deal with the hassle and risk of a lower-quality recording they made themselves?). All it would take is some recording equipment and a couple of towers of CD burners.