My family knows I have SA. I first went to a therapist to see what was going on with me back in 2002. My mother still gets frustrated with me once in a while though. Once she yelled, "Just open your mouth and talk!" Someone on here mentioned they were arguing with their mother about not wanting to go to a family event--well, I went through the same thing, with crying, pleading--the whole 9 yards. I think it was shortly after that I went to the therapist to find out if I had SA. My mom's always been big on therapy, so that wasn't an issue.
As for other people outside my family I usually don't say the term "Social Anxiety" because the few times I have (like to a professor), in explanation of my behavior, they've gotten this blank look on their faces, and had no idea what Social Anxiety was. I think the term's too clinical for most people to handle, so if I feel the need to explain why I turned down their third invitation, or why I'm so quiet and nervous, I just say I've always had a lot of pretty bad shyness problems. But I never know exactly when to make a disclaimer for myself. It always makes me really nervous that they may think twice about hanging out with me if they know I've got shyness problems. Having SA can be so frustrating, partly because of the lack of knowledge other people have about it. Someday!