alt Hacker NewsAmong his various other works, it was Tim Peters along with Gary Robinson who turned pg's "A Plan for Spam" essay into the successful SpamBayes program: https://www.linuxjournal.com/article/6467 .
(EDIT: Robert Woodhead apparently shares in the credit, too: https://www.ceas.cc/papers-2004/136.pdf https://ceas.cc/papers-2004.html . Apparently Rob Hooft was another implementor? I can't find a good source for that though.)
This concept of making the best use of any available data to infer useful probabilities seems like a crude form of some ideas behind current LLMs, BUT they (Peters, Graham, Robinson and Woodhead) were doing this work 20 years earlier.