Totally agree that there is a difference between the micro and the macro in terms of ethnographic practice. Have you come across the terms objectivism and constructionism? Pardon my insulting of your intelligence if you have! I wrote a blog post on them but the basic difference (if applied to Facebook) is that taking an objectivist approach you would argue how it shapes individual behaviours and interactions as opposed to individuals shaping Facebook. In terms of privacy, I suspect that a combination of views would be required as I doubt they can be seen in isolation. This “hidden world” you speak of was discussed in a seminar I attended recently looking at the neutrality of IT systems. I don’t have any references, but can try find some. The presenter tried to say IT systems are neutral but failed to appreciate that they are often built to perform a function which is anything but neutral.

Anyway, apologies for brain dump!