I have 2 friends with it and they are really different from each other. Both also have agoraphobia traits. One is afraid of just being outside and looked at. Especially some situations out there are troublesome. The other one is more about who she is interacting with, she is fine with some and fearful of others, and has a fear of being judged.

Both have other mental issues. For both it seems like the social anxiety is an effect of another issue. But I also know of people who have stand alone social anxiety.

So it looks like it can take many shapes.