Singapore's seediest neighborhood looks downright tame these days. Geylang, a neighborhood northeast of Central Singapore, has long been associated with sex work and other versions of assorted vices. When I was growing up, it was a place of cheap thrills and broken rules. Illegal sidewalk gambling tables (typically sic bo or shells) would appear and disappear to the rhythm of police patrols. So-called "freelancers"—sex workers without an affiliation to any of the neighborhood's licensed brothels—would walk the sidewalks. And enterprising smugglers would sell untaxed Malaysian cigarettes under the cover of darkness.

Today, it's still the tiny, buttoned-down city-state's biggest "licensed" red light district. But something's also changed in the last decade or so. Geylang's streets are quiet. The freelancers are mostly gone. The pimps, men who used to linger on the sidewalks and pull passersby in with a few choice words, have vanished. Same with the gamblers and thrifty smokers.

What happened? If you're like me, you probably thought it had something to do with an increased police presence or a change in the law. A man who told VICE he has worked in the Geylang sex industry for decades said exactly this—that a police crackdown on the illegal, unlicensed sex workers who used to congregate on the streets had a wider impact on the neighborhood, affecting legal sex work establishments as well.

But there's another reason behind the changes in Geylang: smartphones. Prostitution, like nearly everything else, has moved online in Singapore. And the Singaporean government, never one to resist regulation, has responded in kind. The city-state isn't issuing new licenses for brothels, but it will register an "escort service," that connects customers with sex workers.