Keep in mind some children have personalities that are naturally this way. They are not trying to be nosy or annoying but are naturally curious and have personalities that lean toward the social butterfly.

My daughter, is a case in point. She has always been talkative and curious. even at age 2 onward she would walk up to strangers and talk to them and in spite of all the attempts to stop this.

I know it can be annoying and even intrusive but please keep in mind this is a growing mind of a child and no matter what you decide to do, telling her it's none of her business or what not, please do it with kindness!