Widespread London Underground adverts for a brand are a sure way to generate broad awareness. Add in a newspaper article or two and the cross-media awareness builds. This is what is happening with Airbnb, the marketplace for those with and those looking for accomodation across the world. Upwardly mobile people of all cultures and walks-of-life can now find a place to stay pretty much anywhere in the world. As such a new Marketplace, in a similar way to the launch of online dating sites a few years ago, the social tipping-point has been achieved on both the Demand and Supply side. More opportunities for innovative Marketplaces to come!