Off topic question: Why do you believe the ability to sort email into spam and non-spam is super-human? The computerized filter is much, much faster, but I suspect that if you could get 10M sorts from me and 10M from the filter, I'd do better. Yes, that assumes away tiredness, inattention, and the like, but I think that's more an issue of relative speed than anything else. Eventually, the hardware running the spam filter will break down, but not on a timescale relevant to the spam filtering task.