Post: "9 rules of debugging" Each comment: "..and this is my 10th rule: <insert witty rule>" Total number of rules when reaching the end of the post: 9 + n +

Post: "9 rules of debugging" Each comment: "..and this is my 10th rule: <insert witty rule>" Total number of rules when reaching the end of the post: 9 + n + n * m, with n being number of users commenting, m being the number of users not posting but still mentally commenting on the other users' comments.