Why were my HP Ad impressions less than 40% of page views?

It's because HP ad impression does not count all of your impression. It means they does not show the HP premium ad to all kind of visitors. Some advertiser may filter some country , or high paying CPM advertiser might wanted traffic from UK, USA , Canda etc .

As far as I have noticed the ad program prefer organic traffic , I mean traffic from search engines. Direct traffic and traffic from HP community are ignored sometimes.

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.