Podchaser is a really impressive site, its built as a combination of both a directory and community all of course dedicated to podcasting.
I ran a content community site for many years, called Article Alley and I know how important it is to have engagement with your users and members, and this site does it in bucket loads, their feature list is really impressive and I can't think of a site I admire as much as theirs!
Just take a look at the features on my profile page https://www.podchaser.com/users/reportingaccts
Its really rich with great features
- Followers and following
- Top 8 podcast panel
- Activity section
Compared to everyone else it really is streets ahead, I really feel I can learn a lot from them, and I am sure their already great success will only be bettered as they are great in everyway.