I wouldn't suggest doing any heavy lifting to add such a feature. Would it be easier to add a poll feature as they have on Golfwrx?
So, the challenge is this: I can't touch the GCA database, so I can't save anything except in the way we make comments. I can only save things on
your physical computer. Unfortunately, while I'm sure it's technically possible, I don't know how to get those computers to talk to each other. The whole project is very hacky, and the reason I'm doing it is because, well, the system isn't being maintained, so it's a work-around. Thus, anything that stores data (like you would need for a poll), would either need a second database, or would need to integrate making a comment into participation (as information in the comments is a way of storing data).
Now, if you store data in the comments, you could do it really clever way, making it nearly invisible (so as not to bother the other users), and encode it where the extension won't render it anyway. Still, it will leave an artifact, and I think it would stop the extension from being truly invisible to non-extension-users, and that starts to feel very intrusive and inappropriate. This extension should leave no trace.
So, that leaves creating a second database, if I really wanted to share information (votes, likes, etc.) between extension users. The leave-no-trace principle here is still a bit complicated, because if I were to integrate a poll into an external database, I think it would start effecting the discussion, and folks not using the extension might get confused about what people are talking about, because no poll could render on the website. Thus, I think I could only add "background" options in the long run, like votes/karma on posts, even resorting the posts depending on how much other users like them (similar to reddit).
The one of the main reasons I started this project is that, as I started learning that the site has a reputation for being a bit anti-social, I immediately realize I had the capacity to improve that. As I have time, I'm going to keep working on conflict de-escalation features that users can implement, with the next one I'll be focusing on will be thread-specific muting of conflict, so, say, two users are yelling at each other, you can simply say "I don't want to see any post in this thread where these two users quote each other" with a click of a button. That
should translate to the front page (and that gets tricky too), so that you only get update notifications when someone adds something that isn't part of that argument. It's been very interesting to learn write code this way (basically with one and a half hands tied behind my back), as the limitations of not actually controlling the back end make me think really outside the box of the way things should be done.