While Podcasting2.org shows only Podcasting 2.0 features and simply what apps and tools support them, canipodcast.com will go much deeper into widespread usage, especially showing _how_ the features are used, including core RSS features and the "iTunes" namespace.
For example, this will finally document how apps use and handle fallbacks with <itunes:summary>, <content:encoded>, and <description>. And also what HTML formatting is supported in each!