Social media, as I keep saying, has changed the rules completely.
In the pre-digital days of mass marketing, the consumer simply ignored most of the stuff thrown at them, and there was no genuinely effective mechanism to measure the waste.
Now, using the tools of the web the task has changed, as we can measure many dimensions of a messages effectiveness very quickly, and effectively, so the waste is measurable, and the degree of engagement, or “opt-in” becomes a key performance measure of marketing.
This is a whole lot harder than going to lunch with the ad agency, and then just throwing money at the TV or popular magazine in the hope that some of it would stick, as we can now measure not just awareness, but the degree of consumer “opt-in” any communication generates.