I would be interested in seeing someone explore what keywords seem to trigger the reaction, how fast it is, etc... HN has a pretty open API, so it feels like it wouldn't be too hard to make some interesting graphs on how the posts/comments evolve over time.
Heck, I'd be interested in seeing a visualization like that for HN posts in general, but PRC posts are the ones where it seems the most like there's an obvious, reproducible process happening that could be explored and experimented on.