so efficient advertising is moral ...
Inefficient advertising takes advantage of law of large numbers low-cost spammy channels, inundating a large majority with crap they don't care about, wasting their time and even successfully selling people who don't want or like your product.
So in that sense it would seem to be more "moral".
efficient advertising vs privacy - big dilemma ...
efficient advertising => less privacy => immoral ?
http://www.pannone.com/media-centre/articles/ecommerce-artic...
I would suggest that ideal advertising/marketing should have a viral or organically promoted component to it. I'm always going to be more likely to be interested in a product that someone I trust recommends or that I'm directly seeking rather than is being pushed to me. Efficient advertising would ideally be more passive rather than pushy and active and rely on and encourage organic promotion by having the right fit for the audience.
Still I'm just speculating what is meant here.