There's a pragmatic viewpoint of this in terms of personal data:
- Hidden = C:/ drive
- Open = Blog
- Blind = CRM / Gov data (held about you of which you are unaware)
- Unknown = Unknown data
There's a third viewpoint that queries who the "self" and "others" are here. Are there not multiple potential groups of "others". And is "I" always the same?
Anyway time for some cogitating...