"Two thirds of the listings that contain user reviews are for the “Entire home/apartment” room type (listings without reviews are slightly less, at 64%). Because of a New York State law regarding short-term housing, it is almost always illegal to rent a full apartment when the host is not present for less than 30 days."
Anecdotally just surfing around what's currently listed - the vast majority of listings are for whole home/apartments, only a minority are shared.
IMO there are some major shenanigans going on in AirBnb's numbers.
Side note: I hate, HATE, this weasel word, "sharing": "Rosen’s work also examined whether some people would stop renting their apartments to permanent residents and start sharing them only on Airbnb."
IT'S CALLED RENTING. AirBnb hosts are "sharing" their apartments to visitors as much as my local restaurant is "sharing" their food with me.
The claim many are making is that people buy (or even rent) a second property only so they can list it on the site. Which takes away available properties for long term renters or driving prices up. AirBnb's claim of 87% just means that only 13% the NYC hosts are listing secondary properties (ones purchased solely to list on the site). The 87% could be listing their entire home (in which they live) during times they will be away. AirBnb's claim is not really at odds with the numbers stated in the parent comment.
This is commerce, and I would agree that a new, disruptive, form of commerce has been enabled by the web. There will be tremendous benefits, and there will be new problems and externalities. The old regulatory regime will need to adapt, but (in my opinion), this does not mean that zoning laws are now obsolete. Some laws are obsolete, others may be more relevant than ever.
Maybe "micro-commerce" would a better term? In any case, "sharing" is an extremely inaccurate and misleading term here.
(Not that that stopped people from advertising sex work on Craigslist - they're just (slightly) less direct about it).