My upvotes/downvotes are worth 2 points each and my supervotes are worth 6. A person with between 10 and 100 karma on the forum has an upvote worth 1 and a supervote worth 2 (the scaling system is described in this code here I think)
My concern is that this system lends itself to groupthink, whereby the dominant views or topics are liable to get more karma, giving holders of those views more voting power, giving users that makes posts they agree with or that they see as relevant more karma, etc.
Dissenting opinions or posts not of interest to the in-group are liable to be downvoted (although karma is meant to reflect quality or relevance of a post or comment, this is of course misused), which both hides those comments but also puts off dissenting voices from commenting/posting in the future.
The justification for the current system is that people with more karma are more likely to be have better understanding and judgement, less likely to be sockpuppets or trolls and so are better positioned to vote. This is a system ported over from LessWrong (described here).
Concerns about the scaling system have been discussed on the forum previously, for example here.
Is this system more beneficial than harmful?
Retributive downvoting appears to be a bannable offense, according to the forum guide:
https://forum.effectivealtruism.org/posts/yND9aGJgobm5dEXqF/guide-to-norms-on-the-forum#Voting_norms
I suggest you take your case up with the admins.
More generally, perhaps it would be valuable to publicize the voting guide better? E.g. every time my mouse hovers over a voting widget, a random voting guideline could pop up, so over time I would learn all of the guidelines. @Sarah Cheng
I think the risk of groupthink death spirals is real, and I suspect I've been on the receiving end of it. "With great power comes great responsibility."
Do you post on the EA subreddit? Everyone's vote power is equal there:
https://reddit.com/r/EffectiveAltruism/
IMO, the discussion quality on the subreddit is not great. I'm unsure if that's because it lacks scaled vote power, or simply because it has fewer serious EAs and more random redditors. I wonder what would happen if serious EAs made a dedicated effort to post on the subreddit, and bring the random redditors up to speed more etc.