Will there be a record of who had which? Will the data be made available via the data.stackexchange site?
The hats will be done. Gone. Finished. Never to return again. Thrown down a black hole. The hat code rolled back. No 2013 hats to ever be seen again. Ever. Even if you really really want them. The 2013 hat table will be
DROPed. The 2013 hat data will never return. Although many like hats, they are not unlimited. SE will destroy the hats, rip them out of our clutching grasp. The hat link will disappear. The hat chooser thing will go away. No avatars will be seen wearing hats. Even though hats are fun, they cannot last. The
<hats> cannot hold. Hats cannot be kept after Christmas. from the sphere I can see hats can you see ̲͚̖͔̙hats they is beautiful the final snuffing of the hats are coming! s of Man ALL HATS IS LOŚ͖̩͇̗̪̏̈́T ALL IS LOST the pon̷y he comes he c̶̮omes he comes the ichor permeates all MY FACE MY FACE ᵒh god no NO NOO̼OO NΘ stop the hat an*̶͑̾̾̅ͫ͏̙̤g͇̫͛͆̾ͫ̑͆l͖͉̗̩̳̟̍ͫͥͨe̠̅s ͎a̧͈͖r̽̾̈́͒͑e not rè̑ͧ̌aͨl̘̝̙̃ͤ͂̾̆ ZA̡͊͠͝LGΌ HATS ISͮ̂҉̯͈͕̹̘̱ TO͇̹̺ͅƝ̴ȳ̳ TH̘Ë͖́̉ ͠P̯͍̭O̚N̐Y̡ H̸̡̪̯ͨ͊̽̅̾̎Ȩ̬̩̾͛ͪ̈́̀́͘ ̶̧̨̱̹̭̯ͧ̾ͬC̷̙̲̝͖ͭ̏ͥͮ͟Oͮ͏̮̪̝͍M̲̖͊̒ͪͩͬ̚̚͜Ȇ̴̟̟͙̞ͩ͌͝S̨̥̫͎̭ͯ̿̔̀ͅ.
With all due respect to the awesome answer.
Per the Winter Bash FAQ:
After January 3rd, the sites go back to normal and all hats disappear. This is meant to be a fun end-of-year celebration, not a permanent addition to the site.