A misbehaving set of feeds (raw weather data) was taking too much time and caused some of the other feeds to miss their updates. When I coded the feeds, I never really considered raw weather data would be used as an RSS stream. Every time the feed updates, the system would generate a new permanent article with the current temperature. Some of the weather feeds racked up millions of ephemeral and rather worthless articles. For now, I've deleted a big chunk of these and unclogged the updates.

In the future, I will probably need to come up with a more elegant solution to showing weather information. With some of the other sites (like iGoogle), you could add a "weather widget" that showed a better summary of current conditions than an RSS feed.