Do you believe podcasts are effective tools for educational purposes? Watch
I don't believe taking from only one source though. By its nature, podcasts mean you can't directly engage whilst listening to them (though you can afterwards, e.g. on comments or discussion boards - or unless there was a feature/plan to do so). This is why other forms of learning are necessary, though podcasts could be a great supplement in moderation.
Another thing is, not everyone listens to them all in one go. However, podcasts can be used during commutes etc., so can be very useful.