I know it when I hear it
David Brin had an interesting take on it in Earth and other books, notably the non-fiction Transparent Society; and the all-pervasive surveillance society is a sub-plot in Vinge's Deepness in the Sky.
Coming from a small country, and living in a small town ("it has something of the village about it" as an old friend once said), I am acutely aware of both the lack of privacy and the need for privacy.
Iceland, btw, is near unique in publishing everyone's summary income tax record (I believe Norway also does this); this has interesting social effects. Mostly beneficial in aggregate, I think. When I suggested this once in the US, one of the objections I got was from someone who feared his ex-wife would discover his current, higher, income, and demand an alimony adjustment.
Fair enough, except of course it is in the ex's interest to know this information, and indirectly, since alimony is a matter of contract or legal ruling, it is in society's interest that it be fairly and justly paid as agreed.
Well. Consider the recent flap over the NSA phone recordings - and the arguments about whether just tracking the pattern of calls and holding the database of associated information is constitutional, legal or ethical.
Well, here is a functional algorigthm for making that decision: would you accept that information being made public?
Would it be ok with you if the NSA records of who YOU called, and when, and where from, and for how long, was made public, on the Web. Now. For everyone to scan if they so cared to.
You have nothing to hide, right? So nothing to fear.
Well, if it is not ok for the information to be public, then maybe it is not ok for the government to collect, analyse and hold it in secret. Unless of course you trust them, now and forever, no matter who is in office and what the circumstances are.