[eesmith]

If you instead emphasize the 'its audience' part, you may realize an audience may be only one person.

Personal wiki sounds like a fine definition to me.

[bravetraveler]

+1, especially considering the idea that me of tomorrow is not me of today.

"Wiki", if pressed, "documentation" and a curled eyebrow. A strange interrogation.

Closing thoughts: can a wiki not start with one editor? Must the people arrive before the application? Is the information destined for the first wiki it sees?