Re:Email Stamps to Solve Spam
by huhtenberg on Monday November 17, 2008 @08:45PM
(#367664)
> perhaps to click a link, or solve a simple math problem
This approach has rather high false positive rate, i.e. it ends up filtering out something that's not spam. Lots of people loathe callback requests and never bother following up on them. This has little to do with how hard/simple the challenge is, and a lot with the fact that the recipient considers it OK to offload his mail handling headaches onto everyone else.
That's not to mention that this approach basically doubles the volume of spam traffic because From headers are routinely forged.
This approach has rather high false positive rate, i.e. it ends up filtering out something that's not spam. Lots of people loathe callback requests and never bother following up on them. This has little to do with how hard/simple the challenge is, and a lot with the fact that the recipient considers it OK to offload his mail handling headaches onto everyone else.
That's not to mention that this approach basically doubles the volume of spam traffic because From headers are routinely forged.