NaNaPooPoo is an aggregate feed. Actually, it's an aggregate of two aggregate feeds: NaNaPooPoo, an aggregate of regular podcasts; and NaNaPooBooks, an aggregate of serialized audiobook feeds, usually from Podiobooks.com. NaNaPooPoo uses a subpipe called "FeedLimit" to select only the latest audio post in the podcast's feed, and NaNaPooBooks uses "FeedFirst" to select only the first chapter of the book's feed.
I had added a podcast called "Form Letter Rejection Theatre" (a truly excellent short story podcast) to the Poo side. As it turns out, though, the producer has brought the podcast to a halt. She just doesn't produce enough short stories, and didn't have any large number of authors who wanted to share their stories through FLRT, so she ran out of content for that. She's going to be doing a serialized audiobook, instead.
That makes FLRT a whole 'nother thing, a brief anthology of short stories -- effectively, a rather short book. So it made more sense just to offer the first episode. So I moved it over to the Books side of the feed.
The Books side had been entirely Podiobooks content. Oddly enough, the Podiobooks feeds all have the First episodes with the Newest date. I'd changed FeedFirst to work backwards, just to cope with that quirk. But FLRT has the First episode with the Oldest date, just like in the real world... so in NaNaPooBooks, it was offering the last entry.
So I had to go back into FeedFirst. Instead, though, of changing it back to "realtime," I created filters. Based on item:Pubdate, for any Podiobooks feed, it grabs the "newest" entry. For any non-Podiobooks feed, it grabs the "oldest" entry. This gives me back the NaNaPooBooks functionality.
This way, for any podcast I want to include the "first" entry that doesn't "die," I use NaNaPooBooks, and for any podcast where I want the "last" entry that "dies" when it's old, I use NaNaPooPoo.
Cool, huh? I may not be a Nerd. But at least I qualify as a Geek. A fella's gotta know his limitations!