user18404: This is my first post here on meta so please bare with me if it is off-topic. What is the purpose of and origin of hats? 
I just noticed these in the top menu bar when I logged in today on all the Stackexchange sites that I use. 
What do they do? 

user13532: Hats are the feature of an anual event called Winterbash. It’s just a fun thing serving no purpose except for comic relief and igniting competitiveness in those who care at the end of the year.
You get hats for doing certain things. Some hats are public and known while others are secret (spoiler alert). Some users enjoy guessing or confirming the conditions that win you secret hats.
This year, there is also a Youtube video that explains where the idea of hats came from: they were an in-company joke that employees got to put on for performing certain stuff (the sales team for great deals, the dev team to get rid of old cables for something, etc.).
All hats will disappear again in early January and before a new Winterbash season starts next year the Winterbash 2016 page will be removed and no further record of past hats will exist.

18404: <p>This is my first post here on meta so please bare with me if it is off-topic. What is the purpose of and origin of hats? </p>

<p>I just noticed these in the top menu bar when I logged in today on all the Stackexchange sites that I use. </p>

<p>What do they do? </p>
 13532: <p>Hats are the feature of an anual event called <a href="http://stackoverflow.blog/2016/12/Its-Hat-Season-Announcing-Winter-Bash-2016/?cb=1">Winterbash</a>. It’s just a fun thing serving no purpose except for comic relief and igniting competitiveness in those who care at the end of the year.</p>

<p>You get hats for doing certain things. Some hats are <a href="https://meta.stackexchange.com/a/288272">public and known</a> while others are <a href="https://meta.stackexchange.com/a/288284">secret (spoiler alert)</a>. Some users enjoy guessing or confirming the conditions that win you secret hats.</p>

<p>This year, there is also a <a href="https://www.youtube.com/watch?v=CDi_nj1-G6U" rel="nofollow noreferrer">Youtube video</a> that explains where the idea of hats came from: they were an in-company joke that employees got to put on for performing certain stuff (the sales team for great deals, the dev team <del>to get rid of old cables</del> for something, etc.).</p>

<p>All hats will disappear again in early January and before a new Winterbash season starts next year the <a href="http://winterbash2016.stackexchange.com/" rel="nofollow noreferrer">Winterbash 2016</a> page will be removed and no further record of past hats will exist.</p>
