The New York Times celebrates this decision, described here. The upshot is that, in the absence of any positive legislative action, the state of New York is required to give effect to marriages that are legally performed in other jurisdictions.
The court also acknowledges a line of precedents that prohibit state acknowledgement of marriages that are not in accord with "natural law." But in this case:
The natural law exception also is not applicable. That exception has generally been limited to marriages involving polygamy or incest or
marriages “offensive to the public sense of morality to a degree regarded generally with abhorrence” and that cannot be said here.
As the court understands it, natural law "evolves" with the public tastes and sensibilities, at least as they’re perceived by the judges. Legislators who favor this result don’t have to do anything, not even take political heat for supporting same-sex marriage. I’d prefer a more "inclusive" discussion of the state of the "public sense of morality."