That's a really good question, the closest thing to this I think is the 'delta' feature on /r/changemyview. How do you see something like that operating in the reddit ecosystem?
You'd essentially build up a reputation score for Reddit users based on their post history, but this would assume you have some programatic method to verify their expertise between domain knowledge data sources and their comments. I would assume only someone like Facebook would have have the resources to accomplish such as task, as they own the platform, and are actively working to discriminate fact from fiction in user posts.