A lot of things. Kairi went home safe and sound, Sora left to fight the Organization, and Riku did too, but from the shadows. But if you mean what happened to me--

[She buries her toes into the sand, wondering if she'll ever find a way to explain this without sounding over-dramatic.]

I was more a part of Kairi than I ever was a part of Sora. Once their fight was over, I helped them go home, I became a part of Kairi again, and then Naminé didn't exist anymore, because Kairi was whole.