Users with 25k rep can see site analytics. Moderators also have a (more-detailed) view of site analytics.
Today I was looking at the moderator traffic graphs and saw some interesting spikes that I wanted to share with the community. So I went over to the 25k view to take the following screen shot (which I then annotated):
Then I happened to notice that the 25k view provides mouse-over info on individual points on the graph -- and they're all a day early. That very-interesting spike on Erev Yom Kippur (Tuesday, Oct 11) shows up in the 25k graph marked Monday, Oct 10.
How do I know that it's the 25k graph that's wrong? Because all those weekly low points -- which should show up as Saturdays -- are showing up as Fridays. Many of our users and visitors aren't ever online on Shabbat; our weekly traffic dips are definitely on UTC Saturdays, not UTC Fridays.
The existence of any traffic on UTC Saturday shouldn't be seen as a negative reflection on anybody. First off, we're a worldwide community and there are parts of Saturday that aren't Shabbat in most places. Second, we're here for the whole Internet, not just the subset that is Shabbat-observant Jews.