Re: it being awfully quiet: That might be fixable.
The forum links aren't in any obvious permanent location. The ideal place to put a link to the forum would be at the very top of the page, in the nav bar. Before my browser started autocompleting it for me, I ctrl-Fed it. Make the forums easier to find and more people will use them.
Another thing you could do is consolidate the discussions. I go to a forum and find two new posts in the past week, I leave and I don't come back, and the forum stays dead. I've seen this happen in online classes, too, with teachers dividing discussion up so much that people don't find anything to do. (AND THIS WAS LIBRARIANS DOING IT WTF...) You might consider consolidating the genre discussion subforums and the about subforums into one, rather than one for each podcast. Or you might just have a single subforum for each podcast. The idea is that someone coming to comment on this week's show sees the thread about how Alasdair has the best voice or whatever and jump on that one, too; while if it's shut away in another forum they'd never see it.
The only ones that have a volume of threads high enough to really warrant being separate are the episode comments forums, but even then the volume of posts is manageable if they're consolidated.
I'd set it up kind of like this:
Escape Artists:
- Escape Pod Episode Comments
- Podcastle Episode Comments
- Pseudopod Episode Comments
- Escape Artists Consolidated Podcast Metadiscussion
Misc:
- Genre Discussion
- Writing
- Contests
- General Podcasting Discussion
Administrivia/Support consolidated into a single subforum.
Finally, if this isn't already the case, having the text of the story in every instance where it's possible to do so would be nice. I sometimes inflict these stories on my English-studying wife, and having the text helps a lot.
So basically:
Big fat forum links at the top of the page
Consolidate the forums into no more than about 1/2 what you've got now.
More story text, if possible