Now I have looked up Questia a little bit more, and they focus on Social Studies and Humanities. They claim to be the largest online library in this field and they have both online books and journals. They have a newsletter to sign up for. I have done so, and it would be great if a few more people dis, so that we can evaluate this resource for possible subscription.
This database seems to be mainly for highschoolers and up.
You can also become a member of their group at Facebook.