I have a really dumb spam filter on my blog which simply asks that the user "Type the word 'humour', but with American spelling". I've had a couple of complaints that this request is unfair to non-native speakers. My response is that you don't have to know it, you just have to know how to look it up.
(And yes, I saw that this stuff wasn't serious, but I thought it was a worthwhile point to make in any case. CAPTCHAs don't need to be things that users can pass without outside help.)
I have a really dumb spam filter on my blog which simply asks that the user "Type the word 'humour', but with American spelling". I've had a couple of complaints that this request is unfair to non-native speakers. My response is that you don't have to know it, you just have to know how to look it up.
(And yes, I saw that this stuff wasn't serious, but I thought it was a worthwhile point to make in any case. CAPTCHAs don't need to be things that users can pass without outside help.)