Personally I understand people that choose names that fit better in the country/language they (now) live in. Also sometimes people really dislike their names, for whatever reason.
My interest is mostly in people that have a name (or names) on their official documents, but go by something different. Why would you name your kid something and then never use it?
I don't know anything about the adoption process, do children often have a name that is given to them by their birthparents? Any which way, its interesting how people view names and their impact on identity.