I'm probably an introvert, in that I am most relaxed when on my own, but that doesn't always translate to shyness. I have a strange mix of confidence and shyness. I am happy delivering a lecture to dozens or hundreds of people, and usually one of the most vocal people in meetings, but I tend to be shy in one-to-one situations (small talk) with strangers in a social setting. I'm terrible at networking for that reason!