You may have noticed some of our users now have hats around the site, and it might almost be annoying, but we assure you they're all in good fun, and intended to increase site participation!
Here's a link to learn more about the Winter Bash 2012 and what it's all about: https://stackoverflow.blog/2012/12/19/welcome-to-winter-bash-2012/
And here's where we as a community decided we wanted to do hats: Do We Want Hats™?
Yay! Very democratic! We love being democratic and deciding things as a community!
Now that you've learned that we're doing the hats thing, how about going and finding one of your own hats, and joining in! You can find the hats you've collected on your profile page, just near the bottom of the block where your user information is. After that, you can click on that link to open a new dialog, where you can choose one of your existing hats to wear, all around the site! (sorry, doesn't work in chat)