In a way, this reminds me of a high-tech version of the Annotated Sherlock Holmes, which was one of the coolest books ever. It had detailed footnotes on every page -- sometimes so detailed that they went onto the next page. These footnotes would explain the history behind something or state that Watson got the weather wrong for that day in June or speculate on the birthday of Sherlock Holmes.
They could be distracting, however, so sometimes I made myself read the story and then went back and read the footnotes. (I usually read the footnotes after finishing footnoted H. P. Lovecraft stories, for example.)
On the other hand, in an e-book, this would probably drive me nuts.
I know it wouldn't take long for me to find myself reading a flamewar on a Wikipedia entry and forgetting all about the story.