Last time I learned a new language, there wasn't an Internet. Now that I've started Japanese, I'm finding a wealth of online resources.
One of the best is JapanesePod101.com, a daily podcast. The sponsor is a Tokyo-based translation service, which makes perfect sense. Loyal subscribers -- a very targeted audience -- receive daily brand reinforcement.
I also just discovered the dialogue of each daily lesson is spelled out in the "lyrics" section of each podcast's metatag information. This will vastly supplement the already considerable time spent with the podcast.
This could well be a podcasting paradigm: loyal listeners, a relevant sponsor, high engagement, plus a value add feature that enhances an already very immersive experience.