Dear Log,
The Homestar Runner RSS that I set up a while back was a bit atypical as RSS feeds go, in that it listed a whole bunch of things instead of just the newest things. But it turns out that LiveJournal's software didn't like that approach much, so I recently fiddled with it to list only new things.
Internally I implement this with just a hash that tracks the first time an item is seen, like $first_seen{$url} ||= $^T, and then I sort the URLs by time and show the most recent few. That approach would need some ammending if there were constantly URLs coming and going (otherwise the persistent %first_seen hash would get quite large), but that's not the case with the Homestar Runner site, so I got to be lazy. Homsar is my role model.
