As a DJ & promoter myself I need to say, that we used to hope for sales, now we pray for attending, so everybody can promote their stuff.... FOR FREE! ;)
Products & services have to be rewarded ALWAYS in some kind of currency, to create value! It may be even a barter...
Much like here :D
This is the thing. What they are doing will severly reduce the reach of their brand names as artists while some are likely to wave the payment and let their links fly. This will mean that they have to compete less in the advertising space as those who charge will not be there. I feel that this will further speed the pay for what you enjoy models. like here :)