Greetings from Oaxaca! I arrived last week and have since been making myself comfortable as a citizen diplomat (and despite my failure to produce a perfect definition for that term, I think I can apply it to myself, as I'm participating in both study abroad and home stay programs).
I'm currently staying in the home of an incredibly generous woman in Oaxaca, who has hosted some 70 American and Canadian students in the past. Like many participants in the citizen diplomacy process, I'm not sure she would choose to describe herself that way. She seems less concerned with representing Mexico or Oaxaca than in being a gracious host (a task at which she excels).
To be honest, if it weren't for my interest in public and cultural diplomacy, I doubt I'd describe myself that way either. Trying to think of myself as a representative of my country reminds me of elementary school field trips and teachers ominously warning us that were "representatives of our school" who would be disappointing our entire community should we prove incapable of behaving respectfully at the Kennedy Center.
The fact of the matter is that our relationship is both social, cultural and economic, and the primary way in which we define that relationship is as host and guest. But maybe that's one of the reasons citizen diplomacy is so successful. If it has as its objective the improvement of international relations, its motives are less obvious and therefore less suspicious. That objective becomes secondary to successful interpersonal interactions -- the last three feet.