That distinction between passive and active is why i've never been able to get on board with podcasts as a true medium for learning/understanding anything. Its a lack of discipline on my part because I'd end up doing something else as well and the information doesn't really truly get through (that feeling when you realise you've had it on for 10 mins but have not really actually listened to it). That's not possible at all with text as a medium, the brain has to latch on.