How can I see the users who earned the highest number of hats until now on a per-site basis?
The maximum I saw was 19 (earned by two users) but I don't think this is the actual highest one.
Just look at the leaderboard..
At the time of writing, the leader has a total of 31 hats from all sites.
Scrolling down the list gives you the leading number of hats on each site.
For a detailed view on the per-site leaderboard, visit
<site> is the site you're after, like
The Winterbash leaderboard ranks the per-site leaderboard in decreasing order. At the top is the entire network, with sites ranked top-to-bottom below it:
From the above picture we can see that Stack Overflow leads the network-wide race for hats at around 77k, followed by Mathematics with around 12k. We also see a per-site leaderboard listed on the right of each site, again in descending order. For example, Seth on Ask Ubuntu is currently one of maddest hatters having most of the 7k hats on that site.
Clicking on the site in the left-most column provides the per-site leaderboard. Here's the leaderboard for Ask Ubuntu showing Seth sharing the pole position:
To the right is listed 9 of the hats currently owned by each user. If you want to see all the hats owned by any specific user, click on their profile image and on their "hats link":
As you can see, the site-wide leaderboard may have a slight lag in being updated compared to the user-specific profile.