Shameless bounty for my own idea.
TLDR: A site for testing all kinds of weird voting systems! All on top of each other! New users would have to select one or more karma systems (or "axes"), in the same way that new Twitter or reddit or Manifold users are shown a quick menu of broad topics to click "interested" on.
Based on a comment I made about the "EigenKarma Network" on a Discord server, as well as my comment here.
I will judge whether a platform meets these criteria myself. The "most central example" would be "reddit clone with at least 5 coexisting karma axes you have to opt-into".
If LW, reddit, Steemit, or twitter added this functionality, I'd probably consider it "YES", even if it still coexisted with the old "legacy" updoots system in use beforehand.
An example is more in-spirit if they have more karma systems, especially if they coexist chaotically / the site allows users to make more systems willy-nilly. Debatable bonus points if people organize themselves into wacky reddit-style factions based on which axes they prefer.
Funny enough, if EK did this themselves, but kept everything else the same, I'm not sure I'd actually count it. This is because I don't know if they show any user a "homepage" or "feed" with a list of posts in it, and I haven't (yet(?)) made an account to go check. (Are they just some kinda decentralized bot on top of Discord? Because I don't count that as a "YES".).
If I resolve this "NO", or a site meeting "YES" seems unsatisfactory to me, I might start developing this myself. (Possibly as a voting-site where all the posts are actually links to corresponding reddit posts, although "login with reddit" seems not-very-supported for 3rd-party sites.)