To my knowledge we don't measure it, at least not in the way I think you mean. I can't speak for my marketing colleagues but I would assume they reason about i

To my knowledge we don't measure it, at least not in the way I think you mean. I can't speak for my marketing colleagues but I would assume they reason about it. It seems like a complex system to me, which means the approach kind of has to be (1) forming an understanding of the system and (2) deciding whether one is comfortable with the uncertainty. One aspect that makes the cost/benefit assessment quite a bit easier is that we don't only care about how many new paying customers we get. It's also fun to do this kind of advertisement. How many interesting conversations about privacy have been had as a result of people seeing our billboards? That's worth something too.