On Tuesday MSR had a panel about privacy. Alessandro Acquisti asked a probing question: "Why is it that people care so much about privacy?" He was not referring to people protecting their social security or credit card number, but to the near-universally expressed desire to keep one's private life away from the glare of public eyes. He suggested, without further developing it, that there was an issue of control: when someone has information about you, it gives them the means to control you.
That reminded me of Exodus chapter 3, when Moses asks God for his name. I once heard a commentary explain that, in some way, by giving his name to him, God lets Moses have some power over him. (As today is Rosh Hashannah, it also brings to mind the story of the creation, with Adam naming the creatures of the earth, thus also signaling his power over them). Today I found a whole wikipedia article on "True name", about the power of knowing somebody's true name, with mentions of the German folk tale "Rumpelstiltskin", and of many other old references.
The instinct to avoid revealing personal information goes far back in time, and is more deeply ingrained, more primal than the mere avoidance of manipulative marketing ploys!