You forgot to mention the time-zone in your analysis.
Yup, that's a big one. A topic where it is very noticeable is when it concerns monopolies. Negative post or comment about monopolies when Americans are the online majority? Expect to get downvoted into oblivion. Posted when Europeans are the online majority? Up you go. To be clear: this isn't a complaint about downvoting, I'm just pointing out the phenomenon. For example, its possible to go to bed with +7 and wake up…
Yep seen the same phenomenon. There really is too much meaning packed into that one number.