It's now just past what computer people call "2018-01-01T00:00:00" (or, in more human-readable form, "2018-01-01 00:00:00 +00:00").
Some of you will remember that 2017 was exactly 1 day and 1 second shorter than 2016, owing to the leap second added a year ago at 2017-12-31T23:59:60.
Even thought 2017 was that much shorter than 2016, it seemed so much worse. But that's literally behind us now (or at least in the 13/24ths of the world on GMT or ahead of it). Here's looking to 2018 to be just a tiny bit better.
Happy new year!
Just a minute or two ago, Kiritimati (Christmas) Island became the first place in the world to enter 2018. This happens every year—or, at least, every year since Kiritmati moved from UTC-10 (the same clock time as Hawai'i) to UTC+14 (the same clock time as Hawai'i but a day ahead) so they could be the first place on earth to enter the 2000s.
So, just a few minutes ago, that choice caused a fascinating consequence.
As of right now, and until the next person is born on the island (which could be days or weeks because of its small population of 6,500), every single adult on the island will have been born in the 1900s, and every single child will have been born in the 2000s.
As each successive time zone moves into 2018 today, this will continue to be true until the first baby is born before 1am in a particular zone. My guess would be that New Zealand will probably have a baby born before 1am, and eastern Australia certainly will, which means the 1900s/2000s split will only last 3 or 4 hours.
It's just an interesting consequence of a public-relations decision a tiny Pacific atoll made 18 years ago.