Just sharing some potential marketing avenues. You probably are aware of them I suspect, ignore in that case.
I know you submitted to ProductHunt, which is quite neat for finding new things out there. There is also betalist.com which does a similar sort of work, it is smaller than PH though.
There is also https://alternativeto.net/ which has a different focus but it does list Extensions of various sorts, Reddit themed or otherwise.
Stumbled upon http://buzzsumo.com/ and their chrome extension which maybe will be of interest to you since it sort of tries to do something similar though I haven't tested its Twitter integration but its Reddit Engagement count seems hit and miss (it does show a url being on Reddit at multiple subs but sometimes it doesn't).
It is the sort of company that might buy your extension even because your algorithm/system seems much more refined it seems.
Have you heard of https://tildes.net/
It was created by Deimos a former Reddit Admin. Supposed to a reddit alternative, focused on somewhat similar lines but possibly more discussed focused.
It is early days for it. But they may be looking for a tool like yours. Like someone asking you to potential tailor your extension to Twitter Academics discussions, the premise of your extension is very powerful because it brings like minded people together on an already existing platform.
It just requires the right application and it could be instrumental for many communities. Tildes is new, they may be more receptive to this, maybe if you consider it.
You already know HackerNews, it used to have a very high entry barrier which kept casuals out but it is now on slow-steady growth cycle where new users are coming and some naturally don't like but that is only natural.
The extension can be tailored for them as well.
Name Thredd hence is even more justified in a way, it acts as a connecting wire/thread and not just a Reddit thing although currently it is only on reddit.
Just sharing suggestions.