I accidentally visited this site today.
It contains most of the statistics of the users of Stackoverflow.
Is this a site managed by Stackoverflow? And what is the intention of it?
It's all in the about page:
As for the question why it is there I quote from Brent:
I've also built spwho2.com, a front end for some of the slicing and dicing I'm doing. I've got reports like: - Top 100 Tags Last Month - What question tags have the highest closed percentages? - What question tags get the most views? - What question tags get favorited the most often? - What question tags get the most answers? - What question tags are used by people with the highest reputations? I'm working on reports about users, answers, badges and comments next.