I know that the "oh noez social media" attitude that I might have seemed to be promulgating can be overblown, but I don't think that this response doesn't get at the heart of it. It's true that people in your community likely knew about you, and newcomers to a community would have had to build up that background of trust; but I think that there's a huge difference between the sort of reciprocal information sharing that goes on in physical communities, and the undifferentiated, omni-directional outward flow of information that social media makes possible.