Nice post! Found it through the forum digest newsletter. Interestingly I knew Lindy’s Law as the “Copernican principle” from Algorithms to Live By, IIRC. Searching for the term yields quite different results however, so I wonder what the connection is.
Also, I believe your webcomic example is missing a “1 -”. You seem to have calculcated p(no further webcomic will be released this year) rather than p(there will be another webcomic this year). Increasing the time frame should increase the probability, but given the formula in the example, the probability would in fact decrease over time.
I believe there are a few serious flaws in your guesstimate model:
a year has 365.2421905 days, not 365.25. That’s not even rounded correctly!
Smiles per QALY should multiply days in a year with smiles in a good day, instead they are added. They don’t even have the same unit, how can you add them! Insanity!
the post’s karma is far outside of even your 99% interval
Everything else seems quite correct and I agree with your CIs and conclusions.
Also, please find a new name for guesstimate.