The difference is mainly the between the interaction source they provide, social networking web site provide better interaction tools like chatting and sharing photos and videos. Bookmarking sites are used by business oriented people which tends to be share a commercial information which can not be ententaing always.
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.