Airbnb announced this week a new product: "Rooms." Now, when you search for a place to stay on the platform, there's a filter to look for a single room that you can rent out. That's right ...

Airbnb's original pitch sounded more like couchsurfing: a way for local residents to make some extra cash by renting out otherwise idle rooms or beds in their homes. But in most of the top Airbnb ...