I wish this type of social credit existed online.

This is what karma scores on site like this or Reddit try to replicate.

Not really, because such sites really only use upvotes/downvotes as a ranking mechanism. There's theoretically a lifetime upvote/downvote counter (ie. your karma), but other than a number that shows up on your profile, it doesn't have any real impact. You don't really develop a "reputation", for instance your comments get more or less visibility based on your previous commenting history.

There were a couple occasions on Reddit where someone replied to me in seemingly bad faith. I looked and they had negative karma. As a result, I didn’t engage.

But I will agree that it’s far from perfect. It’s also similar to the bar example. A reputation is built one person at a time. It takes a while, with repeated bad behavior, to build a bad reputation with the entire staff or regulars.

> other than a number that shows up on your profile, it doesn't have any real impact.

Certain subreddits you can't comment on until you have a minimum # of karma, some other subs auto-ban you if you contribute or subscribe to other subs.

Yes. And fails. Trolls don't care about karma and can run about being a dick until they're finally banned (possibly years later) rinse and repeat with a new account.