...it's what they do.
Most of the marketing gurus to whom I subscribe preach a movement away from "interupting" people into buying things and not "spamming" them into action. While I do subscribe to most of the theories that today's public does not hear traditional advertising through the noise, there is evidence that good, old-fashioned selling still gets results.
The great thing about online marketing is that it is entirely measurable and therefore different approaches are testable. While I generally agree with Seth Godin that most people do not want to be "over-messaged to," my tests continue to proove that discounts and specials yield more revenue dollars than just product focused messaging. Our "push emails" with discounted special offers yield 30X the revenue of our product-focused tips emails.
Most people say they want fewer communications, but testing shows better response rates with more (within reason).
The trick is to balance the tone of communications and frequency of communications in such a way as to give the "best-feeling" customer experience with the "most-effective" sales approach.
Crazy Eddie might have been shlocky, but he was effective. How do you strike the balance between pushing sales without pushing people away? You test different approaches along the continuum to sees what works best. But the winner will be based on behavior (what they do) not based on expressed preference (what they say).


