As an Airbnb host I would add that there's more to renting out your home than just the money. You can really see how you're helping people travel or visit their family or company headquarters (we've had all of these and more). We can give them a great home, show them all the great stores, restaurants, cafes, and see the huge appreciation for this kind of experience. It's life in another city as people in that city live it. Also remember that here in San Francisco almost all of the hotels are downtown or around Union Square so we can bring people to all the other neighborhoods of the city. I've also been an Airbnb guest and it's amazing as well. It's wonderful to support local people and get great advice about where to go. The site has fundamentally changed the way I think about travel.
People have been renting out their homes to visitor for a long time but what Airbnb has done by creating a central marketplace is incredible. It feels as important as Amazon reinventing online purchases. Like many of the great internet companies Airbnb is ruffling a lot of feathers from intrenched businesses and changing the way people think about their private space. What other company has been so successful at fostering connections between people who have never met in the real world?