I worked on something like this 4 years ago for a site I build called http://www.mftranslator.com http://www.mftranslator.com. The concept that my buddy and I

I worked on something like this 4 years ago for a site I build called http://www.mftranslator.com http://www.mftranslator.com. The concept that my buddy and I created was a Nomadic Post. I should post the spec for it online, but we essentially removed all bot spam from posting on our site without having accounts or captchas and it never interrupted user flow.