"A world where everyone knows exactly what everyone else is doing" (comment #2, by Anonymous to a Harvard Business School article) does seem to be where we're heading: Mark Zuckerberg's vision for Facebook is famously (and controversially) open; the addition of location and presence details to voluntary 'status' data will further erode expectations of privacy...
True, historians think this was pretty much how people lived in the past, but only in the context of the hundred or so people in their small village community. The differences now are many:
- What we do and say is known on a much broader scale; not just in absolute numbers, but the photo, audio and/or video that accompanies our text.
- It's stored, indexed and searchable by others outside our circle - perhaps on a global scale.
- It's "monetized," at least it is grist to the mill of targeted advertising that generates financial benefit to others, not me.
- I'm not the only one storing info about me: my 'friends' tag me in their photos or videos and it takes more effort to opt out by deleting the tags from the public record than most people can be bothered with.
- Confusing small print in shifting Terms and Conditions mean it's possible, even likely, that some database somewhere retains the content, tags and links - even if I think I've deleted them.
Yes, expect 'privacy' to be seen as an historical aberration; but also expect it to have a commercial value in and of itself so that, for some in some circumstances, privacy will be worth the premium costs of time and technology to ensure it exists.
But then it's likely that others will know we've chosen to go "off grid" for a while and that may bring its own challenges!