hCaptcha is basically reCaptcha which you can apply to your site and earn for visitors solving it. I run a forum and so far managed to cash out after hitting the minimum required. (used wordpress plugin) https://link.medium.com/k1KTaRzLmY
From some of their content i found this: Labor is placed into an anonymous open market for bidding. Companies all over the world bid for that labor to complete simple tasks easy for people but hard for machines. Websites earn revenue from that work instead of donating it to Google. Users support the site they’re visiting, and experience less web spam.
So AI/ML companies are the ones who are paying for labeling services so at least there's a market being made here. Also looks like they're using ETH's blockchain to help this work altogether with reputation oracles to check the quality of those solving captcha, so you'd earn based on the quality of visitors (bots vs humans). It should be around 1000 solves for $1?
Also, been seeing some concerning news over reCaptcha basically being a "Google Pixel". Quite concerning but i don't know to what extent they can extract from the mass of info they collect.
I'm curious if other Devs know about this and if there are other alternatives?