I am new to this meta StackExchange community, So I do not have much knowledge about Winter Bash and earning hat meaning in my profile.
Is is just of fun or really mean something.
Winter Bash is a fun event that happens at the end of every year. For a few weeks, as you use the site, you'll earn "hats" that you can put on your avatar. There's a list of hats and a leaderboard at https://winterbash2018.stackexchange.com.
It's all for fun - there's no obligation to participate or anything, and the hats will all disappear after a few weeks. If you don't want to see any of these hat things, feel free to click "I hate hats" in the snowflake dropdown.