A while ago, when I was reading for the purpose of focused learning (technical books, scouring blogs for information about some framework/API, etc.), I began the habit of taking copious notes. My notes are very wordy; it's almost like I'm having a conversation with myself and rephrasing ideas so I can understand them better. OneNote is my weapon of choice - for me it reduces the "barrier to entry" of starting notetaking because it's easy write now and organize later.
Over time, I realized that when I took notes this way, I had a much higher retention rate and a much greater understanding of what I was reading. So much so that when I find myself sitting at my desk or on the couch and "infosnacking," I try to stop and ask myself, "is what I am reading right now worth taking notes on?" If it is, then I start writing. If it's not, I make the effort to tear myself away and either do something that's more productive or something that I really enjoy.