Hacker News Reader

The math is performed by the browser. All the user will have to do is tick a checkbox.

Here's a demo: https://demo.mcaptcha.org/widget/?sitekey=pHy0AktWyOKuxZDzFf...

disclosure: I'm the author of mCaptcha

Commercial spammers use high-end resources, where as users don't have that luxury. So will it not be easy for the spammers to scale the resources to overcome this?

It's not that they can't scale, it's that you want them to HAVE to scale, to make it more expensive to attack your site than another one.

Reply on news.ycombinator.com