I am curious to know who and why gets hats. I have twelve of them and I saw some users having even more than twenty hats. But I have no idea who and for what gave the hats to me and to my fellow members. I found a similar questions: A question on how to earn some hats? Also, what will happen to them in 2014? and https://math.meta.stackexchange.com/a/12098/203663. There were no real answers but some frivol comments.
So I would like to ask again: Who awards the hats and for what achievements?
The awarding of "hats" is a temporal activity carried out on the SE network around the change of the years, known as Winter Bash; by mid January all hats are gone. Very likely next December you can get new hats; the old stay still gone.
For the most part "hats" are like "badges," that is one gets them automatically (see note at the end, though) for some specific action carried out on the site.
A difference is that some of these actions are more unusual and/or time-bound than those for the badges.
For various hats what one needs to do in order to get them is described on the site of the event (see link above). In addition to these regular hats there are secret hats and those become only apparent during the event.
Somebody serendipitously (or intentionally trying things out, informed by earlier experience) triggers a secret hat and then people try to figure out how to do this. You can follow this activity in a dedicated thread on the main meta, already provided in a comment: Winter Bash 2016 - All Hats
And this guessing and searching the secret hats, is in a way a main part of the event. In recent years there even was a hat awarded for correctly guessing what triggers a secret hat (this one was manually awarded by an SE employee in charge of the event).
Actually the hats are awarded on different opportunities and criteria are decided on different hats to whom the hat is to be given. The one who gives hats is Stack Exchange Site.
