Re: @Tiny Iota
I remember listening to a talk noting that a common filtering step in addition is to show the user *two* bits of text - one known, one unknown, and discard all answers that get the known text wrong, on the assumption that if someone gets the known text wrong their answer to the unknown text is also untrustworthy while chances are that if someone gets the known text right they'll at least have given the unknown their best shot. Reduce number of answers to process AND (at least presumably) improve the quality of the answers you DO look at in one fell swoop.
Biting the hand that feeds IT
