I like the thought, Ted, but I'm not sure how much mental exercise is involved in just participating in an online forum. And goodness knows that it's possible to be very well-connected via social media and other internet-based activities and still be unable to handle simple mental tasks like basic arithmetic and real-world figuring - I have some students like that who are glued to their cellphones but need a calculator to multiply 5 times 6 and are daunted by "story" problems, and I teach at a college. I have a feeling Norm had good genes in that respect, and probably had other hobbies (maybe trains?) that kept his mind active. He reminds me a little of my dad, who lived to 93 and solved puzzles on the computer and was active in ham radio until the end. It does seem that way now, in 20-20 hindsight.