The idea that extroversion is a spectrum really speaks to me. I air on the introvert side but I identify with the ambivert description as well. So...I guess I'm an introvert/ambivert!
I also think it's interesting that while we each have our inclinations, we all probably shift where we are on the spectrum on a moment to moment basis, depending on a number of factors. For instance, I typically rejuvenate through being alone, but there are times I clearly get more energy from connection with others.
Does that mean that it's more of a moment-by-moment state, rather than a personality trait? Hmmm : )