As far as I know there is no way to change them. What you are probably seeing are people who have had avatars for years are are visiting Yahoo Answers for the first time. We have not been able to change them since the beginning of the year and there is no word on when it will be available.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.