Re:Ask HN: Would you use an email presorting service like this?
by whichdan on Monday December 09, 2013 @09:23PM
(#6878584)
http://en.wikipedia.org/wiki/Challenge%E2%80%93response_spam...
Further reading if anyone is interested in challenge-response systems.
For a second I thought it was a cute solution to spam, then I realized we'd be in a world of pain if we mailed each other, and both of us replied in such a fashion.
I never mailed him again.
If I have to do work to contact somebody? Well I'll just ignore that person. Sorry.