The problem is that pretty much every commercial entity out there is trying to degrade your privacy. It's usually not because they have some kind of nefarious intentions, but rather, they do it just because they can. They ask for everything they can and the permission to use it in any way they want because it is obviously easier than specifying and asking for what they really need.
So, the next time you go to buy anything, anything at all, make sure you read any privacy notice carefully and understand just how your private information might be used, because once you let the privacy genie out of the bottle, there's no getting it back in there. (more)