You really don't need to sign up with a hosting service to get a free website. You could do it here. Request to manage the page of your sister.
Facebook is so popular now that creating a group page won't hurt. You could try to write the info on Google Knol. A lot of professionals use that to share their knowledge.So, basically any social networking website would be fine.
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.