What are "thumps"? Is this some hipster British slang? And what's supposed to happen if I press a button to up a thump?

Or are you talking about the "thumbs up" / up vote feature we see on Reddit, so that only the most community-voted posts are seen at the top of the thread? That's a solid idea to complement the merit system because the threads shown on the first page are more likely to be read and thus more likely to get considered for a merit point.