The Oblivion list consists only of the questions you encounter in from 'Lessons' and 'Practice' (Practice uses the same set of questions that are contained in Lessons). Once you haven't encountered a question in either Lessons or Practice for 30 days, that specific question gets added to your Oblivion list until you answer it again. ^^
Shame, I thought the new words would be added with the rest. I understand the notes not being added. I've seen afew mistakes on some of them. But with the readings being from news sources, I thought they would have been.