I don't normally make any commerical endorsements here, wouldn't wanna sully TCGS' sterling rep for probity and rational, highly cerebral and dispassionate discourse but I have to call out one particular app for a very specialized class of people - advanced learners of "exotic" languages.
It's an iPhone app called "Music Player - All-in-1".
First of all it's a way better generic music player for iPhone than Apple's piece-of-shit iTunes default app. Wouldn't take much. But that's not my main point here.
Main thing for advanced learners of "exotic" languages such as Chinese and Japanese but really any major language is that the learning materials inventory is a strict pyramid. Tons and tons of same old crappy stuff for beginners. Just go into Barnes & Noble, to their Language/Reference section and pick any language, say French. You'll see a ratio of something like 90/9/1 - 90% will be the same old basic phrases and beginner crap (or maybe 100% in many cases), then if you're lucky there'll be a couple of books at the intermediate level (maybe a book of simple parallel text stories or something), and then nothing for advanced at all.
But even as a fluent target language speaker (such as myself for Mandarin and Japanese), you want to keep learning. There are always tons of specialized and slang words you don't know. Even professional bilingual interpreters need to learn new vocabulary for every single new assignment. And you have to keep your skills sharp if you aren't living in-country and speaking every day, and there's constant in-flow of new idioms, slang, fads and jargon of all kinds popping up. (Plenty of words you don't know in your own native English too, people.)
Of course, there's an assumption that advanced people by definition can find their own material from the real universe of fiction, native mono-lingual dictionaries, feature length movies, newspapers, and so on. That's true to some extent but there are two additional considerations, (i) Access and (ii) Support. Support can be pretty well-handled by all the excellent 3rd party dictionary apps available for the iPhone. But access is a horse of another color.
For reading and text, it's not so bad. You can get websites and newspapers for your target language(s) on your laptop, PC, or tablet. But audio is trickier. Yeah, there are a few cheesy 'world radio' type apps available but you'll find they are mostly weird music and pretty much "off the air" when you'd want to study anyway.
So how about target language movies? Yes and no. Movies first of all have access issues of their own, and more than that, movies are language-sparse. After all, on Day One every filmmaker is taught the first principle: show don't tell. So they're mainly visual. There's actually probably less spoken language for a given type of interaction in a movie than in its typical real-life counterpart. So again, podcast - that's gotta be the thing.
But just try to find any good ones. Again even in the iPhone foreign language app space, most of the so-called podcast programs availabe are FOR BEGINNERS, or intermediate at best. They are highly unnatural and in any case totally unusable for advanced people.
That's where this Music Player app comes in. The app includes a screen list of podcasts, organzied at the top by language. They have all the big languages including the two of main interest to me (though I do Spanish also) namely Chinese and Japanese. Under a given language heading they have a long list of dozens of fantastic podcasts, which are radio shows entirely in the target language and covering all kind of formats and contents, of course news, but also talk, dialog, educational programs, call-in, music mixes, etc.
And they have all kinds of (audio) navigation aids and controls to help you work with the podcast beyond just raw streaming it.
It's the best single resource for advanced learner / maintainer support I've ever found.
