Thoughts I've had:
Total quantity of data available?
Ability to define boundaries?
Ability to enforce those boundaries?
Knowledge of what boundaries to even define?
Who knows what about a person?
How many agents know what?
How aware is the subject of actual knowlesdgee?
How rapidly can that knowledge be further transferred?
Does the surveillor know more of the subject than the subject?
Can the subject access that knowledge?
What level of benefit (or harm) can be transacted on the basis of surveillance? Does this accrue to the subject or others?
Anyway, I think you're forgetting one important dimension: whether the person in question would like that particular piece of information to be known.
That dimension is the setting of boundaries. E.g., "I don't wan't you to know, or share, or seek, or ask of some X." Or if it's acquired, not to share it except as specifically specified -- only with notice, on request, within a given grroup, for (or not for) a specific time, etc., etc.
Or possibly just better questions.
Or perhaps, what possiblities occur to you?