Thanks so much for checking it out, I am the author of the original notebook. I forgot to mention it initially but the timezone is UTC as was already mentioned.
If you have any feedback, would love to hear it as well!
Tangentially related.. When I was at uni I got very bored one summer and started making a spreadsheet of when certain people posted to a message board I frequented. This started with 3 people then became 15. It was very interesting to then plot that because I could make educated guesses about their sleeping habits, when they were at work etc. especially given what they wrote.
I could then make inferences as to their geographical location and other identifying attributes just based on when they were active on this message board. Regrettably I am a data nerd and would love to see such an analysis done on Hckrnews, etc. but I doubt it would be of interest to most others.
One question: which time zone the data is plotted against?