Consider the public traffic data on Quantcast:
Divide the vertical axis by 7 and you get the average visitors in the seven days prior to the day on the horizontal axis. This is the closest I can get to the number published on StackExchange.com, which isn't quite similar at all: the median value of accesses in the last 14 days.
Let me try and painstakingly put the numbers on the same graph:
Is it just me or things don't quite add up?