I’m curious as to how much listening others do, specifically, listening to material that you have no transcript for. For a while, I was listening to all sorts of stuff; I used Global Maverick’s guide to organizing foreign language listening material with iTunes, synced it with my iPod Touch, and had ear buds stuffed in my ears for hours on end. I’m not sure of how helpful it really is.
I’m certainly not arguing against listening to your target language, but I’m not overly confident that one learns a great deal when listening in this fashion. That is to say, sure, hearing something I already know reinforces it. But all of the words and structures I don’t know tend to just fly by me, lost. If it’s something new, whether a word or a grammatical structure, hearing it a dozen times isn’t going to teach me the meaning of it; on listen #12, it’s going to be a big question mark for me, just as it was on listen #1. I suppose one could argue that you could write down unknown things, but that’s going to involve a lot of rewinding, and considering that there’s practically infinite written material for the major languages, it makes more sense to just learn new words from reading.
Obviously, having a transcript of what you’re listening to alleviates this problem; listen to the item in question, then read the transcript and look up unknown words (or vice versa). Then proceed to listening to it until you’re bored of it.