We've just added a new Podcast subscribe action. If you have a podcast on iTunes, you can now ask people to subscribe to your podcast. Since there is no way for us to know if the user actually subscribes due to the iTunes API not providing us with this information, we award the entry when the user clicks to go to iTunes.
If the user already has iTunes installed on their device, it will launch iTunes. If iTunes is not installed, they will be taken to the podcast page on the iTunes website where they will then be prompted to install iTunes.