The song has been the biggest hit of the year from a female artist - no mean feat when established superstars Katy Perry and Miley Cyrus are both promoting their new albums.
2. Blogging about it
The 17-year-old singer contemplated her new age in a typically artful post on her Tumblr blog.
She reminisced about last year's celebrations, when her friends came over to "eat cake and ruffle my hair and talk about pokemon", before taking stock of her rise from obscurity to global stardom.
"this time last year i was making a soundcloud, and a twitter, and a tumblr, all in the name lorde. i had no clue what was going to happen with the music. i hoped it'd be alright.
"last night, i played to a room of people whose names i worship, breathe like fine gold smoke, reverent. there is a lot of stupid shit that comes with being lucky enough to do what i do - a lot of stuff i'd rather skip, if i could - but i wouldn't have traded last night for anything. i felt so warm in the arms of these legends who are good enough to have faith in me."
Lorde said she planned to spend her birthday walking around New York listening to Stevie Nicks and Broken Social Scene and muttering under her breath about her plans for the future.
3. Reading in bed with Eleanor Catton
Lorde capped off her celebrations by hanging out in bed with Man Booker Prize-winning author Eleanor Catton.
New York-based Kiwi Gemma Gracewood posted photos to Twitter of the two celebrated Kiwis catching up.
A pair of brilliant women decide which photo to make public... @EleanorCatton @lordemusic @sonjayelich #nyc pic.twitter.com/XUTAtFVXKT
...And the Official Photo (by mum) pic.twitter.com/8OyapntsNN
4. Getting political
New York Mayor Bill de Blasio got in on the festivities for Lorde's birthday.
The new elected mayor walked on stage for his victory speech as Royals blared in the background.
5. Meeting Bowie and Tilda Swinton
Lorde performed to a star studded audience Museum of Modern Art Film Benefit in New York as her birthday approached.
Afterward she posed for a photo with none other than David Bowie and one of her idols, Tilda Swinton.
Tilda Swinton, @Lordemusic, and @DavidBowieReal at last night's 6th annual #MoMAFilm Benefit hosted by @CHANEL pic.twitter.com/mje4eVEerv
Lorde described meeting Swinton as an "honour" in a tweet sent after the event.
performed at the moma's film benefit honouring tilda swinton. such an honour, that woman is phenomenal. a true heroine
- nzherald.co.nz