One of the hallmarks of a really powerful system is that you find people using it in ways that it was never originally intended nor designed for.
One of our users recently asked for a feature that would only show items in a feed if they contained certain words. This is a pretty neat idea and was added to The List, but while I was mulling over how such a feature would work, it occurred to me that you could do the same thing via a plugin.
I've whipped up a quick-and-dirty first cut of such a plugin and you can download it from here (requires Python). It lets you specify what feed you want to monitor and the keywords (actually regular expressions) that you want to look for. It could still do with a bit of work but it more than does the job, even in its present form.