Supporters of Airbnb hold a rally outside City Hall, in New York. Cities throughout the country have been cracking down on the vacation rental site, prompting protests like these across the country. Bebeto Matthews/AP hide caption

itoggle caption Bebeto Matthews/AP

Our modern relationship to property — namely that it's burdensome to own, and therefore less valuable — has allowed the sharing economy to expand. Gustav Dejert/Ikon Images/Corbis hide caption

itoggle caption Gustav Dejert/Ikon Images/Corbis

The New York City skyline. Thomas Hawk/Flickr hide caption

itoggle caption Thomas Hawk/Flickr

Demonstrators in San Francisco have been protesting outside apartment buildings that have units rented through online brokers. Justin Sullivan/Getty Images hide caption

itoggle caption Justin Sullivan/Getty Images

Taxi drivers protest against Uber, an on-demand car service app, during a 24-hour strike July 1 in Barcelona, Spain. They say it undercuts their business and are calling for the government to ban it. David Ramos/Getty Images hide caption

itoggle caption David Ramos/Getty Images

Airbnb, the online home-rental service, says it will start collecting hotel taxes in a few American cities. Chris Weeks/Getty Images hide caption

itoggle caption Chris Weeks/Getty Images

A search for places to stay in New York City via Airbnb returns plenty of results, despite the practice of short-term rentals being found to be illegal under city and state law. Airbnb hide caption

itoggle caption Airbnb