Chris–good topic. I think that ads do have to be restrained. I am not sure if an ad minutes/hour comparison like “cannot be more than radio” is the right one, but I agree that consumers will have a “tipping point”, and the “tipping point” of “people will not consume if there are this many ads” will be the market force that determines how much advertisers pay for spots, and, indirectly, how much revenue musicians can make from an ad-based distribution model.

I don’t have the knee-jerk negative reaction to ads that some have, but I know that too many ads hits my personal “tipping point” pretty quickly.