This exists! The difficulty of podcast discovery is why I built https://tung.fm. It’s an iOS app and web app to discover podcasts by sharing comments, clips, and recommendations with your friends. The app gives you all this is feed form. Check out what’s trending across the service or just from who you follow. I’ve been spreading the word so that more people can share podcasts which will enable more discovery. If you have any ideas or suggestions on how I can make it better, please let me know. I’m @inorganik on the social web.