[Merry]

I haven't heard it much, though I hear the word anxiety in general conversation when I don't think it used to be used.
I think the issue with social anxiety is that most people get some kind of social anxiety, for example most people get anxious about things like interviews, speeches or presentations, but they wouldn't really describe it as social anxiety, and everyone gets anxiety, because it's completely normal. In the past people might describe themselves as being nervous about doing something or stressed about being in a situation, now they might more accurately describe it as having anxiety at that time.
That's all very different from having a disorder though. I don't know what the statistics for social anxiety disorder are, but I think most people don't have social anxiety disorder, even if they sometimes feel anxious or socially anxious, so I don't think it's something that is talked about much.