Sometimes, justice is served when the identity of someone is revealed and shared. Sometimes it is not. I do not need to search for friends or family members through "social networks" or to reveal much about myself to strangers and vague acquaintances.
In my family history explorations, "long lost" relatives are able to make connections with me after reading my blog posts of relevance to their own explorations of the past. I prefer being in touch by email.
But why do people reveal private information about themselves to strangers? Why would anyone reveal any real facts about themselves in an online forum? Why would anyone believe something written on a screen unless there is some way of verifying the authenticity of the information?