If I understand the substance of this argument, then they're saying that because advertisers chase page real estate instead of advertising transactions, that online advertising will capture at best half the business which once went to the periodical market. It sounds like they're confusing method with goal, but what do I know? I would just assume that in a scarce market, more dollars thrown at less real-estate would result in more expensive real estate. I suppose it's possible that advertising isn't subject to the laws of supply and demand, but really, I'm stupid enough that I'd naturally assume that the object of supply scarcity in this equation would be attention, not the ads themselves.