Paul DiCesare has hosted more than 100 Airbnb guests over the past three years and even started a service that helps other hosts manage their listings. Airbnb has made a huge splash in New York — 416,000 visitors a year, according to the company — but it’s now facing a big backlash. Some estimate that as many as two-thirds of the hosts in New York are violating state housing law, a number that spurred an extended battle with state Attorney General Eric Schneiderman that threatens to halt growth in the company’s most lucrative markets. What happens in New York will have ripple effects in San Francisco, New Orleans, Malibu, and anywhere regulators are cracking down — which is why Airbnb is cranking up the charm.