I agree with that the consumption of knowledge helps us learn. But I am not sure just taking notes does the trick. I think in aiding us learn more the knowledge has to be work and thought out. I believe learning is hard and you have to do something more on the lines or writing articles on the subject or course work to really force your brain to absorb it all.
You're right but I don't quite aim to learn the material as I do to "remember" that I read it and that I can come back to it again in future.
There's only so much space in my brain for specific facts, and I'm pretty poor at dealing with them, but I thrive on knowing where to find the answer to things. The notetaking method I use helps me remember what I've read and to "re-remember" the material rather than to learn it per se.
Taking notes helps in two ways: first, it forces you to think about what you read to extract the salient points; That thinking enhance your understanding and memorisation. Second, it allows you to remember more easily by quickly checking your notes; memory is a dynamic process, and the notes will help you remember the thoughts you had writing them down, therefore the material.