[muzani]

I regard all books as a conversation between the author and the reader. If the author is the only one saying anything, you are passively consuming it. To have a proper "conversation", you have to criticize the content and compare what you know with what the author knows.

HN is actually a nice product that does this - someone can share an article and other people can compare notes (and even have a conversation with the author!)

I also make sure to take notes. If there are no notes worth taking, maybe the book wasn't worth reading in the first place? Some information dense work needs you to even write a kind of glossary, comparing the author's terms as she defines them, instead of using terms you're familiar with. This is especially the case with technical/academic work.