I've been making a podcast discovery app, it's not live yet but the latest home page screenshot is http://imgur.com/a/Bkn7Y (basically: Trending topics, Recommendations (based on social media profile and listening history, subscribed shows, and iTunes charts), and instant search of over 4.5 million episodes across more than 60 thousand shows.)

I may not be able to keep going on it though because of constraints on time and resources. Would be happy to talk to anyone who'd like to partner on this (or ideas about how I can at least handle hosting bills for such a large DB!). firasd at gmail.