The spam filter stuff used Paul Graham's word probabilities described in his seminal article A Plan For Spam. It changed those probabilities a bit, to better account for the number of emails a word appeared in. But in the main, my article was about a statistical method (NOT Bayesian) for combining those probabilities. The word probabilities were Bayesian, but the way of combining them used frequentist statistics. Even so, spam filters that used the technique were always referred to as Bayesian as if nothing frequentist was involved.